I have been testing it a little bit using this diff as a guide to what needs to be tested: https://github.com/vanilla/vanilla/compare/df1476510310939965feb1f4fb713eef5e372e99...2.1 Everything is working as far as I can tell.
Probably needs more testing, this was originally added here: https://github.com/vanilla/vanilla/commit/0fae36 As I understand, you are using sendgrid for the hosted service?
Regarding 2.1.4: I've been testing a bit and everything looks ok. The cleditor fix works, but when you disable it, comments created with cleditor will lose their styling, even things like bold and strikethrough. Not really tragic in my opinion, way better than permanently overriding the SafeStyles setting.