The good news is that Yii2 will go viral sooner than we all even anticipate. There will be new well written wiki pages. What I would like to suggest is having an extra field (could be a drop down) where content contributors can specify for which version of Yii they are writing in their precious articles. The anticipated result is that all readers will be able to easily classify content for the specific version if Yii they are using. Adding a new field would even allow us to filter wiki pages according to a specific Yii version.