I updated mine and my girlfriend's 920 to 8.1. Mine works fine but she is ready to wring my neck lol. Whenever she tries to share photos or whatever the heck she shares to FB, instagram, etc the phone will just show the loading animation for a while and then show a message "unable to share". I have tried normal troubleshooting and next I'm going to uninstall / reinstall the effected apps. But I want to know if anyone else has this issue or has some advice. I'll update her phone with today's release too. Thanks