No, it is not; if you open the new version in the old firmware, the daemon will also crash on startup, as does the old version if you open it in the new firmware.

By the way, I've been working on some UI for uploading/unloading apps from the Pebble:

Apart from this, I've added support for the getWatchToken / getAccountToken JavaScript functions. The first one will return a (MD5) hash of the watch serial number; the second one will return a random number that is persisted between reboots. This means setpebble.com apps should now work and configure properly. I'd still like to add some "per-app" randomly generated salt instead of using the app UUID in order to actually make the hash secure.

Here is the updated testing package.

You still need to manually unpack .pbw files in ~/.local/share/pebble/apps for everything to work. The plan is to eventually register a file association so that downloading .pbw files from the browser will automatically unpack them there.

Smoku, did you get your Jolla back? I would like to send all these changes back, if you are OK with that. Would you prefer small patches, or is a "big" pull request OK?

Apart from the UI + bank/app manager changes, I've done some design ones, such as entirely changing the D-Bus interface (D-Bus naming conventions + lots of new methods), using autogenerated d-bus interfaces/adaptors (still on top of the existing PebbledProxy/Interfaces), rewrote the WatchConnector's read loop (so that it handles fragmented packets), moving the music functionality out into musicmanager.cpp (so that it always uses the last MPRIS service which sent a signal instead of listening for name registrations), and detecting ICU via pkgconfig.