NokiaWPBlog has managed to dig up a fascinating video from February this year, uploaded by M4XW1N which shows a lock screen app on Windows Phone 8.1.
Unlike the others which we have seen shown off at BUILD 2014, which just provides a fancy animations when you unlock, this one appears to show dynamic album art reminiscent of the Zune music player.
It also shows that the music control drop down in earlier builds included album art, something which appears unfortunately to have been dropped.
We understand dynamic lock screen apps are awaiting the final go-ahead from Microsoft, but are still certainly on the way.
Read more at NokiaWPBlog here.