Here you can read the Q&A history.
To get new community support please go to GitHub discussions (KnowageLabs/Knowage-Server · Discussions · GitHub).
Dear Lawi,
If you want to use PostgreSQL, you have the following option:
1) Use the installer to My SQL and then change the DBMS to PostgreSQL
2) Install Knowage starting from the released WAR.
Best regards
Angelo