About HIIT Interval Timer | Cero
Build an interval workout around the way you train. Cero is a flexible interval timer for HIIT, Tabata, circuit training, WODs and HYROX preparation. Set up a quick work/rest timer or program each interval in detail....
Build an interval workout around the way you train. Cero is a flexible interval timer for HIIT, Tabata, circuit training, WODs and HYROX preparation. Set up a quick work/rest timer or program each interval in detail. Distinct colors, large controls and reliable cues keep you focused on the session instead of the clock. BUILD YOUR SESSION . Set work, recovery, sets, warm-up and cool-down. . Create advanced workouts with custom intervals, colors, icons and intensity levels. . Save, duplicate and reorder timers. . Share timers by file or QR code. . Review completed sessions in workout history. STAY IN THE WORKOUT . Follow compatible sessions with Live Activities and Dynamic Island. . Start saved or recent timers from Home Screen widgets. . Use Siri and Shortcuts to start, pause, resume and stop a timer. . Put Gym Display on a larger screen or mirrored TV. . Choose a default song or assign music to individual intervals. . Customize sounds, voice cues, vibrations and background alerts. TRAIN BY HEART RATE Adaptive HR can extend recovery until you reach your target heart rate, then guide hard efforts with low and high alerts. Pair a Bluetooth heart-rate monitor with iPhone or train with heart-rate data from Apple Watch. COUNTDOWN AND STOPWATCH The built-in countdown and lap stopwatch cover warm-ups, station changes, rest periods and race-day practice. Stopwatch sessions continue after you close and reopen the app. ON APPLE WATCH Run saved workouts from your wrist, follow heart rate and use the standalone countdown and stopwatch. Cero can save completed workouts and estimated calories to Apple Health. Automatic iCloud backups help protect saved timers and custom intervals. Useful for HIIT, Tabata, circuits, EMOM-style workouts, boxing rounds, strength and conditioning, indoor cycling, running intervals and hybrid race preparation. Feedback and suggestions: hi@flawless.studio Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Version History Cero for Apple Watch, rebuilt from the ground up. • A redesigned Watch app that's faster and easier to read mid-workout • Workouts run as Apple Watch workout sessions with live heart rate and save to Health • Follow and control a Watch workout from your iPhone with a Live Activity • New complications and a Smart Stack widget show the current interval and time left • Quick timer, countdown and stopwatch redesigned for the wrist, with Always On support • Your timers and appearance sync from your iPhone 4.3.0 2d ago Cero 4.2 makes your progress easier to see and share: • New workout recaps show time, intervals, estimated calories, and heart rate when available. Share your recap as an image. • The stopwatch now charts laps live and shows lap insights. Sessions are saved when you reset, with history you can export as PDF or CSV. • Advanced timers have clearer interval bars and progress, plus refreshed setup screens and timer cards. • Manage Live Activities in Settings on supported devices. Privacy choices and other controls are clearer, too. 4.2.2 5d ago Cero 4.2 makes your progress easier to see and share: • New workout recaps show time, intervals, estimated calories, and heart rate when available. Share your recap as an image. • The stopwatch now charts laps live and shows lap insights. Sessions are saved when you reset, with history you can export as PDF or CSV. • Advanced timers have clearer interval bars and progress, plus refreshed setup screens and timer cards. • Manage Live Activities in Settings on supported devices. Privacy choices and other controls are clearer, too. 4.2.1 Sep 28 Cero 4.2 makes your progress easier to see and share: • New workout recaps show time, intervals, estimated calories, and heart rate when available. Share your recap as an image. • The stopwatch now charts laps live and shows lap insights. Sessions are saved when you reset, with history you can export as PDF or CSV. • Advanced timers have clearer interval bars and progress, plus refreshed setup screens and timer cards. • Manage Live Activities in Settings on supported devices. Privacy choices and other controls are clearer, too. 4.2.0 Sep 24 Cero 4.1 makes it faster to build, run, and review your workouts: • Start from new advanced and quick timer templates, including open-ended manual intervals. • See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings. • Export your workout history as a PDF or CSV file. • Improved custom interval duplication and timer layouts. 4.1.3 Sep 21 Cero 4.1 makes it faster to build, run, and review your workouts: • Start from new advanced and quick timer templates, including open-ended manual intervals. • See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings. • Export your workout history as a PDF or CSV file. • Improved custom interval duplication and timer layouts. 4.1.2 Sep 18 Cero 4.1 makes it faster to build, run, and review your workouts: • Start from new advanced and quick timer templates, including open-ended manual intervals. • See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings. • Export your workout history as a PDF or CSV file. • Improved custom interval duplication and timer layouts. 4.1.1 Sep 17 Cero 4.1 makes it faster to build, run, and review your workouts: • Start from new advanced and quick timer templates, including open-ended manual intervals. • See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings. • Export your workout history as a PDF or CSV file. • Improved custom interval duplication and timer layouts. 4.1.0 Sep 16 Your timer can do a lot more now: • Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts. • Timer Music lets you choose a default song or set different music for individual intervals. • Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach. • Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control. • Gym Display gives you a clearer view on a large screen or mirrored TV. • Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups. • A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch. • The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections. A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.1 Sep 14 Your timer can do a lot more now: • Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts. • Timer Music lets you choose a default song or set different music for individual intervals. • Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach. • Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control. • Gym Display gives you a clearer view on a large screen or mirrored TV. • Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups. • A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch. • The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections. A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.0 Sep 14 This app has been updated by Apple to prepare for watchOS 27 compatibility. No new features are included. - Solve minor issues 3.7.3 06/18/2025 - Solve minor issues 3.7.2 06/03/2025 - Solve minor issues 3.7.1 04/03/2025 - Translated Cero to Korean, Japanese, Malay, Thai, Arabic, Indonesian, Norwegian, Danish, Swedish, and Finnish - Solved minor issues 3.7.0 04/02/2025 - Performance improvements 3.6.4 03/30/2025 - Performance improvements 3.6.3 03/18/2025 - Performance improvements 3.6.2 03/17/2025 - Performance improvements 3.6.1 03/08/2025 - Performance improvements 3.6.0 03/06/2025 Hey! Here we go with a new update!: • Performance improvements. Thanks for your valuable feedback and suggestions at support@cero.app 3.5.7 11/06/2022 Hey! Here we go with a new update!: • Performance improvements. Thanks for your valuable feedback and suggestions at support@cero.app 3.5.6 10/05/2022 Hey! Here we go with a new update!: • Performance improvements. Thanks for your valuable feedback and suggestions at support@cero.app 3.5.5 03/08/2022 Hey! Here we go with a new update!: • Performance improvements. Thanks for your valuable feedback and suggestions at support@cero.app 3.5.4 01/20/2022 Hey! Here we go with a new update!: • Performance improvements. • Implementation of Apple's app tracking transparency. Thanks for your valuable feedback and suggestions at support@cero.app 3.5.3 06/21/2021 Hey! Here we go with a new update!: • Performance improvements. Thanks for your valuable feedback and suggestions at support@cero.app 3.5.2 06/10/2021
Previous Versions
Here you can find the changelog of HIIT Interval Timer | Cero since it was posted on our website on 2021-12-16 15:31:47.
The latest version is 4.3.0 and it was updated on 2026-10-15 18:59:01. See below the changes in each version.
HIIT Interval Timer | Cero version 4.3.0
Updated At: 2026-10-15
Changes: Version History Cero for Apple Watch, rebuilt from the ground up.
• A redesigned Watch app that's faster and easier to read mid-workout
• Workouts run as Apple Watch workout sessions with live heart rate and save to Health
• Follow and control a Watch workout from your iPhone with a Live Activity
• New complications and a Smart Stack widget show the current interval and time left
• Quick timer, countdown and stopwatch redesigned for the wrist, with Always On support
• Your timers and appearance sync from your iPhone 4.3.0 2d ago Cero 4.2 makes your progress easier to see and share:
• New workout recaps show time, intervals, estimated calories, and heart rate when available. Share your recap as an image.
• The stopwatch now charts laps live and shows lap insights. Sessions are saved when you reset, with history you can export as PDF or CSV.
• Advanced timers have clearer interval bars and progress, plus refreshed setup screens and timer cards.
• Manage Live Activities in Settings on supported devices. Privacy choices and other controls are clearer, too. 4.2.2 5d ago Cero 4.2 makes your progress easier to see and share:
• New workout recaps show time, intervals, estimated calories, and heart rate when available. Share your recap as an image.
• The stopwatch now charts laps live and shows lap insights. Sessions are saved when you reset, with history you can export as PDF or CSV.
• Advanced timers have clearer interval bars and progress, plus refreshed setup screens and timer cards.
• Manage Live Activities in Settings on supported devices. Privacy choices and other controls are clearer, too. 4.2.1 Sep 28 Cero 4.2 makes your progress easier to see and share:
• New workout recaps show time, intervals, estimated calories, and heart rate when available. Share your recap as an image.
• The stopwatch now charts laps live and shows lap insights. Sessions are saved when you reset, with history you can export as PDF or CSV.
• Advanced timers have clearer interval bars and progress, plus refreshed setup screens and timer cards.
• Manage Live Activities in Settings on supported devices. Privacy choices and other controls are clearer, too. 4.2.0 Sep 24 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.3 Sep 21 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.2 Sep 18 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.1 Sep 17 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.0 Sep 16 Your timer can do a lot more now:
• Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts.
• Timer Music lets you choose a default song or set different music for individual intervals.
• Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach.
• Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control.
• Gym Display gives you a clearer view on a large screen or mirrored TV.
• Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups.
• A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch.
• The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections.
A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.1 Sep 14 Your timer can do a lot more now:
• Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts.
• Timer Music lets you choose a default song or set different music for individual intervals.
• Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach.
• Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control.
• Gym Display gives you a clearer view on a large screen or mirrored TV.
• Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups.
• A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch.
• The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections.
A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.0 Sep 14 This app has been updated by Apple to prepare for watchOS 27 compatibility. No new features are included.
- Solve minor issues 3.7.3 06/18/2025 - Solve minor issues 3.7.2 06/03/2025 - Solve minor issues 3.7.1 04/03/2025 - Translated Cero to Korean, Japanese, Malay, Thai, Arabic, Indonesian, Norwegian, Danish, Swedish, and Finnish
- Solved minor issues 3.7.0 04/02/2025 - Performance improvements 3.6.4 03/30/2025 - Performance improvements 3.6.3 03/18/2025 - Performance improvements 3.6.2 03/17/2025 - Performance improvements 3.6.1 03/08/2025 - Performance improvements 3.6.0 03/06/2025 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.7 11/06/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.6 10/05/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.5 03/08/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.4 01/20/2022 Hey! Here we go with a new update!:
• Performance improvements.
• Implementation of Apple's app tracking transparency.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.3 06/21/2021 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.2 06/10/2021
HIIT Interval Timer | Cero version 4.2.1
Updated At: 2026-10-08
Changes: Version History Cero 4.2 makes your progress easier to see and share:
• New workout recaps show time, intervals, estimated calories, and heart rate when available. Share your recap as an image.
• The stopwatch now charts laps live and shows lap insights. Sessions are saved when you reset, with history you can export as PDF or CSV.
• Advanced timers have clearer interval bars and progress, plus refreshed setup screens and timer cards.
• Manage Live Activities in Settings on supported devices. Privacy choices and other controls are clearer, too. 4.2.1 Sep 28 Cero 4.2 makes your progress easier to see and share:
• New workout recaps show time, intervals, estimated calories, and heart rate when available. Share your recap as an image.
• The stopwatch now charts laps live and shows lap insights. Sessions are saved when you reset, with history you can export as PDF or CSV.
• Advanced timers have clearer interval bars and progress, plus refreshed setup screens and timer cards.
• Manage Live Activities in Settings on supported devices. Privacy choices and other controls are clearer, too. 4.2.0 Sep 24 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.3 Sep 21 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.2 Sep 18 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.1 Sep 17 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.0 Sep 16 Your timer can do a lot more now:
• Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts.
• Timer Music lets you choose a default song or set different music for individual intervals.
• Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach.
• Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control.
• Gym Display gives you a clearer view on a large screen or mirrored TV.
• Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups.
• A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch.
• The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections.
A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.1 Sep 14 Your timer can do a lot more now:
• Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts.
• Timer Music lets you choose a default song or set different music for individual intervals.
• Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach.
• Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control.
• Gym Display gives you a clearer view on a large screen or mirrored TV.
• Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups.
• A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch.
• The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections.
A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.0 Sep 14 This app has been updated by Apple to prepare for watchOS 27 compatibility. No new features are included.
- Solve minor issues 3.7.3 06/18/2025 - Solve minor issues 3.7.2 06/03/2025 - Solve minor issues 3.7.1 04/03/2025 - Translated Cero to Korean, Japanese, Malay, Thai, Arabic, Indonesian, Norwegian, Danish, Swedish, and Finnish
- Solved minor issues 3.7.0 04/02/2025 - Performance improvements 3.6.4 03/30/2025 - Performance improvements 3.6.3 03/18/2025 - Performance improvements 3.6.2 03/17/2025 - Performance improvements 3.6.1 03/08/2025 - Performance improvements 3.6.0 03/06/2025 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.7 11/06/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.6 10/05/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.5 03/08/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.4 01/20/2022 Hey! Here we go with a new update!:
• Performance improvements.
• Implementation of Apple's app tracking transparency.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.3 06/21/2021 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.2 06/10/2021 Hey! Here we go with a new update!:
• Visual corrections and usability improvements.
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.1 05/17/2021 Hey! Here we go with a new update!:
• We have redesigned the timer view. Now we make better use of space, showing all the info more clearly.
• Horizontal mode for timers.
• Remarkably improved battery usage.
• Fixed some random crashes in some iPads.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.0 05/04/2021
HIIT Interval Timer | Cero version 4.2.1
Updated At: 2026-10-01
Changes: Version History Cero 4.2 makes your progress easier to see and share:
• New workout recaps show time, intervals, estimated calories, and heart rate when available. Share your recap as an image.
• The stopwatch now charts laps live and shows lap insights. Sessions are saved when you reset, with history you can export as PDF or CSV.
• Advanced timers have clearer interval bars and progress, plus refreshed setup screens and timer cards.
• Manage Live Activities in Settings on supported devices. Privacy choices and other controls are clearer, too. 4.2.1 3d ago Cero 4.2 makes your progress easier to see and share:
• New workout recaps show time, intervals, estimated calories, and heart rate when available. Share your recap as an image.
• The stopwatch now charts laps live and shows lap insights. Sessions are saved when you reset, with history you can export as PDF or CSV.
• Advanced timers have clearer interval bars and progress, plus refreshed setup screens and timer cards.
• Manage Live Activities in Settings on supported devices. Privacy choices and other controls are clearer, too. 4.2.0 6d ago Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.3 Sep 21 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.2 Sep 18 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.1 Sep 17 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.0 Sep 16 Your timer can do a lot more now:
• Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts.
• Timer Music lets you choose a default song or set different music for individual intervals.
• Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach.
• Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control.
• Gym Display gives you a clearer view on a large screen or mirrored TV.
• Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups.
• A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch.
• The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections.
A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.1 Sep 14 Your timer can do a lot more now:
• Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts.
• Timer Music lets you choose a default song or set different music for individual intervals.
• Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach.
• Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control.
• Gym Display gives you a clearer view on a large screen or mirrored TV.
• Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups.
• A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch.
• The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections.
A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.0 Sep 14 This app has been updated by Apple to prepare for watchOS 27 compatibility. No new features are included.
- Solve minor issues 3.7.3 06/18/2025 - Solve minor issues 3.7.2 06/03/2025 - Solve minor issues 3.7.1 04/03/2025 - Translated Cero to Korean, Japanese, Malay, Thai, Arabic, Indonesian, Norwegian, Danish, Swedish, and Finnish
- Solved minor issues 3.7.0 04/02/2025 - Performance improvements 3.6.4 03/30/2025 - Performance improvements 3.6.3 03/18/2025 - Performance improvements 3.6.2 03/17/2025 - Performance improvements 3.6.1 03/08/2025 - Performance improvements 3.6.0 03/06/2025 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.7 11/06/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.6 10/05/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.5 03/08/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.4 01/20/2022 Hey! Here we go with a new update!:
• Performance improvements.
• Implementation of Apple's app tracking transparency.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.3 06/21/2021 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.2 06/10/2021 Hey! Here we go with a new update!:
• Visual corrections and usability improvements.
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.1 05/17/2021 Hey! Here we go with a new update!:
• We have redesigned the timer view. Now we make better use of space, showing all the info more clearly.
• Horizontal mode for timers.
• Remarkably improved battery usage.
• Fixed some random crashes in some iPads.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.0 05/04/2021
HIIT Interval Timer | Cero version 4.1.3
Updated At: 2026-09-24
Changes: Version History Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.3 2d ago Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.2 6d ago Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.1 Sep 17 Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.0 Sep 16 Your timer can do a lot more now:
• Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts.
• Timer Music lets you choose a default song or set different music for individual intervals.
• Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach.
• Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control.
• Gym Display gives you a clearer view on a large screen or mirrored TV.
• Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups.
• A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch.
• The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections.
A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.1 Sep 14 Your timer can do a lot more now:
• Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts.
• Timer Music lets you choose a default song or set different music for individual intervals.
• Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach.
• Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control.
• Gym Display gives you a clearer view on a large screen or mirrored TV.
• Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups.
• A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch.
• The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections.
A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.0 Sep 14 This app has been updated by Apple to prepare for watchOS 27 compatibility. No new features are included.
- Solve minor issues 3.7.3 06/18/2025 - Solve minor issues 3.7.2 06/03/2025 - Solve minor issues 3.7.1 04/03/2025 - Translated Cero to Korean, Japanese, Malay, Thai, Arabic, Indonesian, Norwegian, Danish, Swedish, and Finnish
- Solved minor issues 3.7.0 04/02/2025 - Performance improvements 3.6.4 03/30/2025 - Performance improvements 3.6.3 03/18/2025 - Performance improvements 3.6.2 03/17/2025 - Performance improvements 3.6.1 03/08/2025 - Performance improvements 3.6.0 03/06/2025 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.7 11/06/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.6 10/05/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.5 03/08/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.4 01/20/2022 Hey! Here we go with a new update!:
• Performance improvements.
• Implementation of Apple's app tracking transparency.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.3 06/21/2021 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.2 06/10/2021 Hey! Here we go with a new update!:
• Visual corrections and usability improvements.
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.1 05/17/2021 Hey! Here we go with a new update!:
• We have redesigned the timer view. Now we make better use of space, showing all the info more clearly.
• Horizontal mode for timers.
• Remarkably improved battery usage.
• Fixed some random crashes in some iPads.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.0 05/04/2021 Hey! Here we go with a new update!:
• Introducing Quick Timers. A new exclusive feature for Cero Pro that will allow you to configure your Simple timers directly from your Apple Watch.
• Dark appearance style.
• Show or hide Heart Rate in your Apple Watch.
• Improved sync logic.
Thanks for your valuable feedback and suggestions at support@cero.app 3.4.0 04/12/2021 Hey! Here we go with a new update!:
• Some performance improvements have been done.
Thanks for your valuable feedback and suggestions at support@cero.app 3.3.1 03/21/2021
HIIT Interval Timer | Cero version 4.1.1
Updated At: 2026-09-17
Changes: Version History Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.1 35m ago Cero 4.1 makes it faster to build, run, and review your workouts:
• Start from new advanced and quick timer templates, including open-ended manual intervals.
• See elapsed time during your workout and track progress with the new wave animation. Wave effects can be switched off separately for simple and advanced timers in Settings.
• Export your workout history as a PDF or CSV file.
• Improved custom interval duplication and timer layouts. 4.1.0 17h ago Your timer can do a lot more now:
• Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts.
• Timer Music lets you choose a default song or set different music for individual intervals.
• Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach.
• Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control.
• Gym Display gives you a clearer view on a large screen or mirrored TV.
• Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups.
• A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch.
• The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections.
A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.1 2d ago Your timer can do a lot more now:
• Adaptive HR can extend recovery until you reach your target heart rate and guide hard efforts with low and high alerts.
• Timer Music lets you choose a default song or set different music for individual intervals.
• Live Activities and updated Dynamic Island layouts keep compatible sessions visible and within reach.
• Home Screen widgets, Siri and Shortcuts make saved timers quicker to start and control.
• Gym Display gives you a clearer view on a large screen or mirrored TV.
• Share and import timers with a file or QR code, review completed sessions in workout history, and protect your setup with automatic iCloud backups.
• A configurable lap stopwatch is now available on iPhone. Countdown and Stopwatch have also arrived on Apple Watch.
• The refreshed design includes a new app icon and improvements to timer reliability, background alerts and heart-rate connections.
A useful update for HIIT, Tabata, circuit training and HYROX preparation. 4.0.0 3d ago This app has been updated by Apple to prepare for watchOS 27 compatibility. No new features are included.
- Solve minor issues 3.7.3 06/18/2025 - Solve minor issues 3.7.2 06/03/2025 - Solve minor issues 3.7.1 04/03/2025 - Translated Cero to Korean, Japanese, Malay, Thai, Arabic, Indonesian, Norwegian, Danish, Swedish, and Finnish
- Solved minor issues 3.7.0 04/02/2025 - Performance improvements 3.6.4 03/30/2025 - Performance improvements 3.6.3 03/18/2025 - Performance improvements 3.6.2 03/17/2025 - Performance improvements 3.6.1 03/08/2025 - Performance improvements 3.6.0 03/06/2025 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.7 11/06/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.6 10/05/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.5 03/08/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.4 01/20/2022 Hey! Here we go with a new update!:
• Performance improvements.
• Implementation of Apple's app tracking transparency.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.3 06/21/2021 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.2 06/10/2021 Hey! Here we go with a new update!:
• Visual corrections and usability improvements.
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.1 05/17/2021 Hey! Here we go with a new update!:
• We have redesigned the timer view. Now we make better use of space, showing all the info more clearly.
• Horizontal mode for timers.
• Remarkably improved battery usage.
• Fixed some random crashes in some iPads.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.0 05/04/2021 Hey! Here we go with a new update!:
• Introducing Quick Timers. A new exclusive feature for Cero Pro that will allow you to configure your Simple timers directly from your Apple Watch.
• Dark appearance style.
• Show or hide Heart Rate in your Apple Watch.
• Improved sync logic.
Thanks for your valuable feedback and suggestions at support@cero.app 3.4.0 04/12/2021 Hey! Here we go with a new update!:
• Some performance improvements have been done.
Thanks for your valuable feedback and suggestions at support@cero.app 3.3.1 03/21/2021 Hey! Here we go with a new update!:
• Heart Rate sensors integration! Now you can link your Bluetooth sensors to show your heart rate and track it into Apple Health.
• Some other performance improvements have been done. In the last version, some random crashes occurred to some of you. It won't happen again!
Thanks for your valuable feedback and suggestions at support@cero.app 3.3.0 03/18/2021 Hey! Here we go with a new update!:
• We have improved Cero for Apple Watch! Now you are able to handle your music from the own app. We have also improved the UI making your experience better without scrolls in the timer screen.
• The automatic sync has been removed, it will come back when we get a flawless performance. Instead of that, now you will see a Sync button in your Apple Watch. Quite easy, right?
• Some other performance improvements have been done. In the last version, some random crashes occurred to some of you. It won't happen again!
Thanks for your valuable feedback and suggestions at support@cero.app 3.2.0 03/09/2021
HIIT Interval Timer | Cero version 3.7.3
Updated At: 2026-09-10
Changes: Version History This app has been updated by Apple to prepare for watchOS 27 compatibility. No new features are included.
- Solve minor issues 3.7.3 06/18/2025 - Solve minor issues 3.7.2 06/03/2025 - Solve minor issues 3.7.1 04/03/2025 - Translated Cero to Korean, Japanese, Malay, Thai, Arabic, Indonesian, Norwegian, Danish, Swedish, and Finnish
- Solved minor issues 3.7.0 04/02/2025 - Performance improvements 3.6.4 03/30/2025 - Performance improvements 3.6.3 03/18/2025 - Performance improvements 3.6.2 03/17/2025 - Performance improvements 3.6.1 03/08/2025 - Performance improvements 3.6.0 03/06/2025 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.7 11/06/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.6 10/05/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.5 03/08/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.4 01/20/2022 Hey! Here we go with a new update!:
• Performance improvements.
• Implementation of Apple's app tracking transparency.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.3 06/21/2021 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.2 06/10/2021 Hey! Here we go with a new update!:
• Visual corrections and usability improvements.
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.1 05/17/2021 Hey! Here we go with a new update!:
• We have redesigned the timer view. Now we make better use of space, showing all the info more clearly.
• Horizontal mode for timers.
• Remarkably improved battery usage.
• Fixed some random crashes in some iPads.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.0 05/04/2021 Hey! Here we go with a new update!:
• Introducing Quick Timers. A new exclusive feature for Cero Pro that will allow you to configure your Simple timers directly from your Apple Watch.
• Dark appearance style.
• Show or hide Heart Rate in your Apple Watch.
• Improved sync logic.
Thanks for your valuable feedback and suggestions at support@cero.app 3.4.0 04/12/2021 Hey! Here we go with a new update!:
• Some performance improvements have been done.
Thanks for your valuable feedback and suggestions at support@cero.app 3.3.1 03/21/2021 Hey! Here we go with a new update!:
• Heart Rate sensors integration! Now you can link your Bluetooth sensors to show your heart rate and track it into Apple Health.
• Some other performance improvements have been done. In the last version, some random crashes occurred to some of you. It won't happen again!
Thanks for your valuable feedback and suggestions at support@cero.app 3.3.0 03/18/2021 Hey! Here we go with a new update!:
• We have improved Cero for Apple Watch! Now you are able to handle your music from the own app. We have also improved the UI making your experience better without scrolls in the timer screen.
• The automatic sync has been removed, it will come back when we get a flawless performance. Instead of that, now you will see a Sync button in your Apple Watch. Quite easy, right?
• Some other performance improvements have been done. In the last version, some random crashes occurred to some of you. It won't happen again!
Thanks for your valuable feedback and suggestions at support@cero.app 3.2.0 03/09/2021 Hey! Here we go with a new update!:
• Finally, we have it... Say "Welcome!" to the automatic Apple Watch sync! You won't need to keep your timers synced manually anymore, Cero will take care of it!
• There was a small issue with the iPad multitasking... It is now fixed!
Thanks for your valuable feedback and suggestions at support@cero.app 3.1.2 03/06/2021 Hey! Here we go with a new update!:
• We have fixed an issue that provoked some iPads to crash. Now that silly bug... is gone! Enjoy it!
Thanks for your valuable feedback and suggestions at support@cero.app 3.1.1 03/03/2021 We highly appreciate your suggestions and comments, so in this version, you will find the following improvements:
• iPad multitasking and landscape orientation support.
• Solve some random crashes.
• Some visual tweaks. 3.1.0 03/01/2021 We highly appreciate your suggestions and comments, so in this version, you will find the following improvements:
• Improvements in the Countdown feature.
• Some minor fixes and improvements. 3.0.1 02/25/2021
HIIT Interval Timer | Cero version 3.7.3
Updated At: 2026-08-21
Changes: Version History - Solve minor issues 3.7.3 06/18/2025 - Solve minor issues 3.7.2 06/03/2025 - Solve minor issues 3.7.1 04/03/2025 - Translated Cero to Korean, Japanese, Malay, Thai, Arabic, Indonesian, Norwegian, Danish, Swedish, and Finnish
- Solved minor issues 3.7.0 04/02/2025 - Performance improvements 3.6.4 03/30/2025 - Performance improvements 3.6.3 03/18/2025 - Performance improvements 3.6.2 03/17/2025 - Performance improvements 3.6.1 03/08/2025 - Performance improvements 3.6.0 03/06/2025 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.7 11/06/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.6 10/05/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.5 03/08/2022 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.4 01/20/2022 Hey! Here we go with a new update!:
• Performance improvements.
• Implementation of Apple's app tracking transparency.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.3 06/21/2021 Hey! Here we go with a new update!:
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.2 06/10/2021 Hey! Here we go with a new update!:
• Visual corrections and usability improvements.
• Performance improvements.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.1 05/17/2021 Hey! Here we go with a new update!:
• We have redesigned the timer view. Now we make better use of space, showing all the info more clearly.
• Horizontal mode for timers.
• Remarkably improved battery usage.
• Fixed some random crashes in some iPads.
Thanks for your valuable feedback and suggestions at support@cero.app 3.5.0 05/04/2021 Hey! Here we go with a new update!:
• Introducing Quick Timers. A new exclusive feature for Cero Pro that will allow you to configure your Simple timers directly from your Apple Watch.
• Dark appearance style.
• Show or hide Heart Rate in your Apple Watch.
• Improved sync logic.
Thanks for your valuable feedback and suggestions at support@cero.app 3.4.0 04/12/2021 Hey! Here we go with a new update!:
• Some performance improvements have been done.
Thanks for your valuable feedback and suggestions at support@cero.app 3.3.1 03/21/2021 Hey! Here we go with a new update!:
• Heart Rate sensors integration! Now you can link your Bluetooth sensors to show your heart rate and track it into Apple Health.
• Some other performance improvements have been done. In the last version, some random crashes occurred to some of you. It won't happen again!
Thanks for your valuable feedback and suggestions at support@cero.app 3.3.0 03/18/2021 Hey! Here we go with a new update!:
• We have improved Cero for Apple Watch! Now you are able to handle your music from the own app. We have also improved the UI making your experience better without scrolls in the timer screen.
• The automatic sync has been removed, it will come back when we get a flawless performance. Instead of that, now you will see a Sync button in your Apple Watch. Quite easy, right?
• Some other performance improvements have been done. In the last version, some random crashes occurred to some of you. It won't happen again!
Thanks for your valuable feedback and suggestions at support@cero.app 3.2.0 03/09/2021 Hey! Here we go with a new update!:
• Finally, we have it... Say "Welcome!" to the automatic Apple Watch sync! You won't need to keep your timers synced manually anymore, Cero will take care of it!
• There was a small issue with the iPad multitasking... It is now fixed!
Thanks for your valuable feedback and suggestions at support@cero.app 3.1.2 03/06/2021 Hey! Here we go with a new update!:
• We have fixed an issue that provoked some iPads to crash. Now that silly bug... is gone! Enjoy it!
Thanks for your valuable feedback and suggestions at support@cero.app 3.1.1 03/03/2021 We highly appreciate your suggestions and comments, so in this version, you will find the following improvements:
• iPad multitasking and landscape orientation support.
• Solve some random crashes.
• Some visual tweaks. 3.1.0 03/01/2021 We highly appreciate your suggestions and comments, so in this version, you will find the following improvements:
• Improvements in the Countdown feature.
• Some minor fixes and improvements. 3.0.1 02/25/2021
HIIT Interval Timer | Cero version 3.7.3
Updated At: 2025-06-18
Changes: - Solve minor issues
HIIT Interval Timer | Cero version 3.7.3
Updated At: 2025-06-18
Changes: Jun 18, 2025
Version 3.7.3
- Solve minor issues
HIIT Interval Timer | Cero version 3.7.1
Updated At: 2025-04-03
Changes: Apr 3, 2025
Version 3.7.1
- Solve minor issues
