Same as some other reviewers, after the update, my classic pebble is now stuck at firmware update mode forever. Tried many times and resets and the pebble got back to a screen showing a picture with a finger touching on a phone and a text like "pebble.com/app". The watch is useless now.
4/22/2016 update:
Just recovered my watch. Forgot all Pebble bluetooth connections on iphone first, then press the up, back and select buttons on the watch at the same time until the watch resets to the Pebble logo to enter into recovery mode, then run the Pebble app in iphone and it will re-download the firmware to the watch, then follow the instructions to pair with the watch and reconfigure it. Vola, it works again.
mmlc1 about Pebble™