- Use Poco 2's built-in backup feature (in the File menu) or close Poco and copy everything from the Poco directory to a backup directory.
- No, you certainly do not need to install v3 over v2. Until you're sure you want to switch to v3, you can run both programs on your computer:
- Backup Poco 2. This is just a safety measure. You can never have too many backups!
- Disable Check Mail on Startup. If you have Poco 2 set to check new mail on startup, disable this setting. (see Options/General/Startup)
- Install Poco 3 to a new directory. I think that Poco 3 will install to a new directory by default, but just in case I'm wrong, make sure to pay attention during the setup process. The installation tool will ask you where you want to install Poco 3, so just make sure that whatever it suggests is not the same as your current Poco 2 directory.
- Launch Poco 3. Skip the setup wizard. Go to File/Import/Data from another Poco installation... and point Poco 3 to your Poco 2 "poco.ini" file. Poco 3 will copy data from Poco 2, but it won't change your Poco 2 installation. Poco 3 will close automatically after the import.
- Update Spellcheck Dictionaries.
If you were using any foreign-language spellcheck dictionaries, you'll need to download new ones; the spellcheck component has been updated in Poco 3.
- Restart Poco 3. If you want to be able to receive all of your mail in both Poco 2 and Poco 3, you need to make sure Poco 3 is set to Leave Mail on Server for all of your accounts (see Accounts Setup.)
- Check your directory settings. See Options/General: Backup Directory and Options/General/Directories. Make sure that none of the directories is the same as your Poco 2 directories.
- Compress All Mailboxes. (The command is in the Mailboxes menu). More info on Compressing here.
- When you're done using Poco 3, close it and launch Poco 2 again to reset the "Check mail on startup" setting.