I just went through this. Contact partnersuccess at roku.com and they should send a form requesting the required information. Hopefully you have the support of the current developer. Keep in mind that any information stored in a user's registry is tied to the Dev ID used to package the channel. You'll need an old package (you should be able to download it once the transfer is complete) and the password (get it from the old developer) in order to rekey the development box before packaging your updates. If nothing was stored in the registry or you don't care if that information is lost, you don't need to rekey.
-JT
Roku Community Streaming Expert
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