The OM20 was released in 1983. It was called OM G on some markets. It existed in chrome and in black finish.
It is basically an OM10 with a manual shutter speed ring built-in and a few other advances. These include a PC-sync flash connection, [LED] warnings in the viewfinder, built-in manual metering, and provision for attaching a steady grip. It didn't replace the OM10, but was available alongside it.
Olympus OM20 35mm Film Camera with Vivitar 28mm f/2.8 Lens
It is basically an OM10 with a manual shutter speed ring built-in and a few other advances. These include a PC-sync flash connection, [LED] warnings in the viewfinder, built-in manual metering, and provision for attaching a steady grip. It didn't replace the OM10, but was available alongside it.
Olympus OM20 35mm Film Camera with Vivitar 28mm f/2.8 Lens