Since it clearly mentions that you must have 22.214.171.124 or later then you should follow the supported upgrade path.
You may also consider upgrading to 12c instead.
You may try not to upgrade to 126.96.36.199 in a training environment but eventually you have to follow the right procedure.
188.8.131.52 is not certified with R12.2.5. Min version certified is 184.108.40.206
I have installed 12.2 fresh and now planing to upgrade it to 12.2.5, in the notes it is mentioned to upgrade the DB to 220.127.116.11, can i skip it and leave it to the current version of the DB i understand it is recommended but if i leave it to the current version 18.104.22.168 will 12.2.5 get installed without any issue ?
Thanks and regards,
You can't skip it because this is the supported approach. The step to upgrade the database to 22.214.171.124/126.96.36.199 is a MUST and it's not just recommended as you understand.
Please implement the steps under "Section 3: Upgrade Database to 188.8.131.52 or higher" in (Doc ID 1983050.1) before you proceed.