General info regarding the 15454 M2 shelf is contained in the attached R9.2 Reference Guide (large file). This shelf assembly is part of the MSTP for DWDM operation.
You have not indicated what you are needing for your replacement system.
As far as I am aware, 15305 is not EOL, but, as far as I can tell, there hasn't been any new features on the platform for quite some time. Someone else may have more information.
Good luck!