I just finished updating the Metacello configurations for Seaside 2.8, Magritte 1.0 and Pier 1.0. I’ve tested the configurations in Pharo 1.0 and GLASS 1.0-beta.87 running against GemStone 2.3 (i.e., the appliance).
The change log for the most recent Seaside2.8 checkins indicates that Seaside2.8 should run in Pharo 1.3, but I haven’t tested in that environment. In a comment, Lukas confirms that Seaside2.8 runs in Pharo 1.3. You can download images from the Lukas’ continuation integration server.
If you want to run the latest configurations of Seaside2.8 and friends in the appliance, then follow the update instructions on Getting Started with GLASS.