Actually, not another format, just an improvement to an existing format.
I'm guessing it would be true that older computers would not be able to read these jpegs unless they get an update, but the jpeg standard is implemented via the libjpeg library which will likely be available and included in any jpeg handling software as a matter of course.
JPEG 9 with lossless JPEG compression immediately availableIt is available under a fee-free license with open source code. After 15 years of continuous development, the upgrade to the new version 9 enables for the first time an effective lossless image compression
mode and thus offers end users and industrial adopters a high added value. The Code is ready for download at the IJG Development Site.
http://www.infai.org/jpegThis is nothing like Adobe, Fuji or whoever re-inventing the wheel and expecting everyone to catch up. When you think about it, everytime a manufacturer brings out a new camera, we have to wait for the RAW format to be supported in the software we use. If (that's a big IF) the camera manufacturers support the lossless jpeg output along with or instead of RAW then there would be no requirement for a constant update to support new RAW formats.