I upgraded to Krypton yesterday, which went smoothly (although my music library had to be rescanned??), but I cannot fint the MyOSMC button anymore? A choice or an ommision?
Which skin are you using?
Have you checked if the addon is enabled?
Music Library is extended significantly in Krypton therefore rescan.
I tried both the Default Kodi and Confluence skins. It wás enabled before the upgrade.
To be honest, I was not aware it was a add-on. Your remark made me look under Programs, and there it was. 
Just relocated. Thanks for the tip!!!
And thanks for the info about the rescanning. 
After the upgrade you should initially had the new OSMC Skin which still has MyOSMC on the main menu.
I default use Confluence… And previously it was in there too…