So finally I had to retire the mobile apps - they were coded in the Actionscript programming language that was getting harder to update with each new version of iOS, and the promise of being able to publish to all platforms had long since faded.
I decided the best way forward was to develop a mobile-suited web app instead, which has a lot of benefits for updating and for use across devices (browsers on iOS & Android, as well as on PCs). It has a similar but simpler format to the Kanji Connect app, which I have found to be really useful & enjoyable as a way to make you think about the connections between kanji form, readings & meaning.
To record your progress with the kanji & vocab that you study, just sign up for free with your Google account. :
One big nice new feature of this app is the ability to import your own vocab to study! From the profile page, just follow the 'Import Kanji' link and copy-paste in your kanji/reading/meaning rows. Maybe you have some Anki sets, or big lists of saved lookups from dictionary apps, or Jreading webreader add-ons - it's time to actually review them!
I do hope to continue to develop further functionality in future, such as linking to sentence examples, and adding some other game modes - but this depends on how many people use it. So if you like it, let your Japanese-studying friends know about it!
Oliver Rose in Kansai, Japan