I had this problem too.. But when i downloaded 102. it had an option to update existing... That worked great!

I closed the application and launched it again and then the email account reappeared. I then had some issues with the trash folder in that account having been renamed (which also messed with my filters) and the language settings being all screwed up, but these were fixable with some minor effort and multiple closings and relaunchings of the app. All in all, I haven't been very impressed with my initial experience of 102...