The OM20 was released in 1983. It was called OM G on some markets. It existed in chrome and in black finish.
It is very similar to the OM10 but disposes of the need for a manual adaptor with a manual shutter speed ring built-in around the lens, like the single digit models, there are also a few other advances. These include a PC-sync flash connection, backlit shutter speeds and warnings in the viewfinder, built-in manual metering, flocked mirror chamber and the provision for attaching a steady grip 1 or 2.
The top deck of the camera was revised, with the mode selection and ISO selection dials changed giving arguably better operation. The OM20 also featured a 'Lumi-Micron Matte' viewscreen, which was marketed to be 1 f-stop brighter than the previous model. A removable grip is included with the camera, improving it's handling. It didn't replace the OM10, but was available alongside it.