OpenACS 4.x is the porting effort of ACS 4.2 to a fully open-source platform, specifically PostgreSQL to begin with. The goals of this effort are to:

• Achieve full ACS 4.x functionality on a fully open-source platform
• Lead the way in porting the ACS to other databases
• Allow many developers to write OpenACS packages on their own (e.g. eliminate the bottlenecks)
• Create a "fat binary core" which can, at the flip of a switch, run on Oracle or PostgreSQL.