I would take the version numbers on the Admin page with a pinch of salt. This article explains the version numbers that you are seeing - https://support.oracle.com/knowledge/Enterprise%20Performance%20Management%20and%20Business%20Intelligence/2289049_1.htm… .
With regards to your upgrade process, take a look at the Oracle upgrade guide. In summary you'll need to install WebLogic and OBIEE 188.8.131.52.0 and then apply the latest OBIEE bundle patch -
Patch 29640387: OBI BUNDLE PATCH 184.108.40.206.190716.