You can get all the required information from Community in the following link: Pegasystems Documentation
Fulfilling the details will provide you the requested information (fully detailed upgrade proces and upgrade guide for your application server / database).
In this other link in Community you can find Pega Platform changes with upgrade impact for the different versions: Pegasystems Documentation
The upgrade steps were available in the below link:
Please find the appropriate upgrade guide on selecting the application server and database server. Please find the following link for the combination of the Postgres DB with the tomcat application server.
@palas3 Thank you for sharing the details. In our case we would be updating from 8.1.4 to 8.5. So I was looking for Pega update approach documents for both in place and out of place update.
@GARCM Thank you for sharing the details. In our case we would be updating from 8.1.4 to 8.5. So I was looking for Pega update approach documents for both in place and out of place update. Also Pega Platform changes with any update impact from 8.1.4 to 8.5