This constraint was removed about 14 days ago. Without this constraint, errors like the following will show up....
[30/Aug/2022:14:07:29.820625][3102633.7f152c28d700][-conn:openacs.org:default:0:196214-] Error: rp_handler no-script-abort: errorMsg can't read "message(forum_id)": no such variable while serving GE T /forums/message-view?message_id HTTP/1.1 : ad_url </forums/message-view> maps to file </var/www/openacs.org/packages/forums/www/message-view.adp> : TCL LOOKUP VARNAME message : can't read "message(forum_id)": no such variable : while executing : "forum::get -forum_id $message(forum_id) -array forum"
Probably, in many more cases, the incorrect removal of the notnull constrain performed by [1] requires the same fix.