For reference, the USA version of the TVA voice mail systems is not protected and is "end user" installable. It's a lot of fun to see end users struggle with the installation :-)

If you upgrade from 0027 to any version, you have to step through the other versions (notably at least to 2.1 then 3.something) or you lose all messages. I think you can reinitialize the system and just install your 3.x version, but I've never had the luxury of being able to do that.

Carl