The last time I tried to update the addon, the Blizzard API was limited and a lot of items and spells were missing from it.

I don't know if it's still working like that, but to be able to update the addon to the most recent version of the game, the parser needs to be updated so it supports the last changes made to the Blizzard API, and if the API is still broken, a new parser will be needed using a different API or a different approach (WoW Head web scrapper?).

Anyway, the process will be slow as all items and spells should be downloaded again.