I imagine someone at some point will want to see the tweaked specs for styles uploaded to Brewers Friend. Just released this morning on BJCP.org. I myself am only just beginning to review the changes. Best way I can see what's what is to download both 2015 and 2021 in Word, then run a Compare tool to see what actually changed. I'm wading through it right now.
https://www.bjcp.org/news/bjcp-rele...rus6n_6anxVMwrYE7xu__h0Yxwxdom6JKGrNmS-1RmVis
https://www.bjcp.org/news/bjcp-rele...rus6n_6anxVMwrYE7xu__h0Yxwxdom6JKGrNmS-1RmVis