This app has been updated by Apple to prepare for watchOS 27 compatibility. No new features are included. • Messages now take half the time to send/receive, because, in the underwater CODEC (modem), I now have each symbol (now a 3-tone chord) encoding 2 bits at a time instead of just 1. • Also, I improved its (message) reliability: Each symbol/chord now contains an extra "parity" component. This in turn allowed me to turn up the gain for some extra range.

• Added a magnetic compass/heading rose display shield over the conversation panel, which appears after 30 seconds of inactivity but disappears upon any crown turning, button pushing, button activation, incoming message, or sleep/wake cycles. • During the compass rose display, the general info display at upper-left rotation’s heading display will be of the true heading, not the magnetic heading as usual. The graphical compass rose heading is always magnetic. When the graphics rose disappears, the upper-left's small heading display once again goes back to magnetic. True status is shown by the word "TRUE" underneath the upper-left display. • Several of the signals keys now have versions of the new PADI "I see plastic (and will go get it)" (P for plastic hand signal) signal. • Support has been added for water temperature and depth display (presented as both imperial and metric units) in the rotating general info area at upper-left. • The water temperature rotating display is retained for an additional 5 minutes after exiting the water. • The general info area will now skip directly to the next available (displayable) item rather than linger longer on the previous "good" item when encountering unavailable items. • For the Help/SOS mode, the delay between the SOS signals has been shortened. • The concept of a quick wrist wiggle/vibrate rotation has been added as an additional SELECT gesture, as well as punch left-right as an additional BACKSPACE gesture. This works well in addition to the wheel when composing messages. • Fixed a text-to-speech processing bug that would sometimes cause "comma smiley" to be said in certain situations. • Some of the BOAT/SHORE/HOME-containing messages were not compressing well due to a string table mismatch typo bug. • Made the medium and fast banner scroll/crawl speeds a bit faster. • Fixed a too-soon-crawl termination bug (caused abruptness in rare circumstances). • Added the concept of checking for whether we are on Watch Ultra series hardware. We use water resistance rating as a proxy indicator for this. We have it affect the start warning message; we add a note that on non-Ultra screen sizes, the UI is clipped in places unacceptably, but, then again, this app is only intended for the Ultra, so, make a plea to upgrade to it. • The Info/About box now shows a recognizable pseudo-English-word cookie generated from the build version. • Improve the copywriting of the UI user permission text box for motion manager access. • For the icon: fix the export params be no-alpha (directly) and black background premultiply, so that a tiny white fringe does not appear when rendered on the watchOS app chooser; subtly fix brilliance of the orange border of the app icon. • Internal source code improvements have been added that are designed for future plans to port to iOS.

Supports watchOS 10: Fixed UI incompatibilities; works with watchOS 9.x in a slightly different UI mode. Added speech synthesis as an alternative to encoded-tone-modem audio. Version display behavior at info box bottom now matches documentation.