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Amazfit T-Rex 3 Pro update improves freediving and BioCharge

March 5, 2026 Ivan Jovin Firmware update, Smartwatch 2 min read

Zepp Health is pushing out a new firmware update for the T-Rex 3 Pro, bringing the rugged outdoor watch up to version 4.5.3.3. The update weighs in at 11.84MB and focuses mostly on freediving and BioCharge improvements.

If you own one of these watches, you should see the update prompt appear in the Zepp Health app before long, if it hasn’t arrived already. It’s not the most headline-grabbing release, but there’s enough here to make it worth installing.

What’s in the update

The biggest focus is on freediving. Zepp Health has optimised the depth algorithm for both Outdoor Freediving and Indoor Freediving workouts, and also fixed depth chart issues in those same modes. If you’ve been using the T-Rex 3 Pro underwater, this one is worth grabbing.

Beyond that, the BioCharge algorithm has been refined once again, the turn reminder page during route navigation in workouts has been tidied up, and a crash issue that could occur in workout records during ultra-long outdoor sessions has been resolved. A general bug fix round closes things out. And that’s pretty much it.

What’s still missing

This update won’t satisfy everyone. Lactate threshold, which made its debut on the recently launched Amazfit Active 3 Premium, is still nowhere to be seen on the T-Rex 3 Pro. Automatic rerouting and a golf app are also absent, features that a number of T-Rex 3 Pro owners have been hoping to see added.

That said, we expect that lactate threshold will make its way to other watches soon via firmware. There is no reason for it not to. The T-Rex 3 Pro seems like a natural candidate given its positioning, but there’s no timeline to point to just yet.

For now, version 4.5.3.3 is a solid if unspectacular maintenance release. Worth updating, just don’t expect it to transform the watch.

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