Has the dev database already been upgraded? A lot of times developers will work locally but use the same DB as their dev server(s). If so, your database has already been upgraded and you just need to deploy your updated project. If not, followed the instructions here:
I've done this on a number of occassions and haven't had any issues.
One thing to note is the instructions state to "Package the upgraded website without
the configuration files from ~/App_Data/Sitefinity/Configuration
.". This statement isn't entirely true. I've had to add/merge a number of config files for the upgrade to run smoothly. Initially, I didn't and had missing modules/controls. Specifically, the Lists module was missing because ListConfig didn't exist and the upgrade didn't create it. The same can be said for new toolbox controls. I would add/merge the following config files prior to deployment: