While updating from 2402 LTSR CU1 to CU2 in my test environment, I foolishly installed the Director CR offered as part of the update as I was keen to see the new features Citrix has been touting. Our test environment database is on SQL Server 2016, and the update failed midway through and seemingly can't be fixed. Note: This failure happened after the CU2 update ran all its pre-update checks successfully. 2402 LTSR is compatible with SQL Server 2016, but I imagine that the new Director installation makes modifications to the database that require a newer version of SQL. I had made powered-down snapshots of both test DDCs but we don't take backups of that particular test SQL server, so no easy rollback was available. With the test database now copied to an SQL 2019 server, a DBA and I have been hacking through a recovery for the last day or so just for the experience. (I could have rebuilt the test infrastructure twice by now, but we don't often get these opportunities.) After a lot of effort, we have the test environment running on SQL 2019, but the Test Site button in Citrix Studio (mmc version) fails with 30 errors. All catalog updates work, and every catalog/delivery group/storage/connection test works except Test Site. I'll try removing and readding the Delivery Controllers, and then I may call Citrix to see if they've got a clean-up script. Reattempting the Director (CR version) install may also be an option. Anyway, posting this mainly as a warning to others to not be me. :)

Thanks for sharing! Interesting point on SQL requirement for Director CR. I was considering using it and we are still on SQL 2016 so maybe not! You put a lot of effort to fix it but ultimately you would never do that in prod as you have a backup. So I would rebuild at this stage even if I get it, it's now a challenge for you so good luck!

I ran into similiar issues while upgrading to CVAD 2411 with SQL 2016. I found a reddit comment in this thread

Just ran into this this past weekend also, and found that Reddit post because I searched for “STRING_AGG”. FYI - as a test we commented out this section and got past the issue. Although I’m not sure what affect this will have.

Yep, we either commented out that same section or at least seriously considered doing so, and then ended up copying the database to a newer SQL server. At this point, I wish we'd commented out the lines. We're still seeing errors after copying the database to a newer SQL server and using PowerShell to repoint the database even after double checking our database connection. All day-to-day Citrix functionality I've tested in this test site is working except for the new Director and the Test Site function, which throw errors. I may open a case with Citrix before rebuilding. Thanks for your comments, guys. :)