I installed the 2019 update and started playing along with my guitar, had a moment of "whaaa???" as it seemed BIAB was playing 1/2 tone sharp.
Read the posts and saw the comment about "cheap headstock tuner," which I use. Got out my old tuning fork (remember those?) and it agreed with BIAB, not my guitar or its tuner.
Lesson learned - tuner battery gets weak, it tunes flat. Blame the battery (or cheap headstock tuner), not BIAB!!
Now I won't wonder why on earth I tuned to Eb!!
Happy new year, BIAB fans!