I submitted the 2.5.0 iOS app update to the store last week, so it should reviewed by early next week (although they have a bit of a backlog). This update improves TTS accuracy for Japanese, sadly disables it for Chinese (too inaccurate), updates some audio files, and fixes a bunch of bugs.
The other main update is that we finally added an option of whether to download sentences or not. All sentences you've already downloaded will still be there, so if you don't want to see them, do a Clear Local Data after you get the update. If you do want to keep seeing them, make sure to enable that option when you get the update, because it defaults to off.
Why will it default to off? We've been seeing a lot of sync problems due to gnarly sentences gumming up the works, and it also makes syncs take a lot longer to do, so if you're not using the sentences, you should see more reliable sync behavior. (Also, it turns out that it will cut Skritter's server costs a lot to only sync sentences to users who actually want them.)