Hi-- Back on this question: https://support.mozilla.org/en-US/questions/1295662 I reported back when the most critical issues from 78 stopped making Thunderbird completely unusable, after a couple of bug fix updates came out. But my last post/question still hasn't been acknowledged or addressed--LDAP address books now do show up in the list, but I haven't gotten a working LDAP lookup since 78 disrupted everything. The fixes to everything else in the Address Book don't appear to have corrected whatever's wrong there. As noted in the original comment, lookup of user certificates for encrypting emails has been questionable for a while, but at least core functionality of user lookups had been working up until 78. Before now I was the only one I knew definitely experiencing this but I just got a note from someone asking about the same broken LDAP behavior and it's definitely something that should work. Every time I try to do a search I get prompted to authenticate vs the LDAP, then the popup goes away and nothing happens. Thanks.