Thread:Project:Support desk/Notice: Undefined property: DatabaseMysql::$mTrxDoneWrites in D:\wiki\TechWiki\includes\db\Database.php on line 512/reply (6)

No! If you downgraded, you would open the security wholes, which 1.20.1 intends to fix. Since 1.20.1 already is released and since the development process (fixing these security ssues) happens publicly, the exact issues are known. Knowingly opening these wholes again would not be clever. ;-)

Instead have a look at. Sooner or later a fix will be presented there (which you can then try out).