Whatever the change, I just find it weird that a main software update is pushed out without any information on what it does. I cannot recall this having been done before.
It looks like 5.30 was what 5.10 was supposed to be, but without the 'not able to turn DND Off during sleep' bug and other update complications that others have reported on the forum. So the changelog is from 4.10 to 5.30, and therefore no reason to mention fixing the DND bug etc. Had it been a 5.10 to 5.30 changelog, then the things broken from 4.10 to 5.10, that have been fixed in 5.30, would be listed. Hope that all sounds logical; it did in my head as I was writing this :D