Question: would this make all the old items be obsolete? I assume yes.
Which? The XML format or the expanded location/rarity scheme.
The XML will be in the next release. The way it's going to work is that the new files have an "x" on the end, like MS did with their new MS Office XML formats. Only instead of .docx, we're going to have .itemsx, .girlsx and .rgirlsx.
When the game loads, it will load both formats. Which is to say, it will load any .itemsx, .girlsx and .rgirlsx file it finds. Once it's done that, it will load any old format files unless it already loaded the XML version of the same file. So we have backwards compatibility. Also, Solo's editor will allow you to convert existing files to the new formats.
For the expanded rarity scheme, I haven't nailed down the details yet, but I expect I could make that work much the same way. If there are location tags in the file, the game will use them. If not, it'll go by the rarity attribute, the same as it does at the moment.
So either way, the answer is probably "no"
