All, I've looked at a few cases of this reported and individuals were using the wrong version. Please ensure if you're on 4.2 that you're using the file called "[JIMMO] User Join Date in Post - USE ME IF YOURE ON 4.2". After uploading the file and looking at the plugin details you should see that the plugin version is 4.0.0. If you see any other version than that you uploaded the wrong file and will need to download that file from the Marketplace. Thanks.