Currently when one updates from 1.1 to dev all the webform blocks will "disappear". This is because the default setting for the "Display as block" on the webform configuration form is off.

There should be an update function that checks for webform blocks that have been set to be displayed in a region and set this display as block option to 1. Note: this will still result in a broken update for users who use the context module to set block visibility, maybe a check against that would be good too.