Seems like we are advised to check for things that might be off or unexpected when we convert from a previous version. I'm wondering how a multi-conversion from all the way back to v 13 might end up. I'd be curious, littlechris1977, if you or anyone else attempts this, how it turns out. Please report back
And along those lines, if this is attempted, definitely save a backup of the initial import into v 21, and then run a test.