The introduction of the RiscPC in 1994 and its later StrongARM upgrade raised issues of incompatible code sequences and proprietary squeezing (data compression). Patching of applications for the StrongARM was facilitated and Acorn's "UnsqueezeAIF" software unsqueezed images according to their AIF header. The incompatibilities prompted release by "The ARM Club" of its "Game On!" and "StrongGuard" software. They allowed some formerly incompatible software to run on new and upgraded systems. The version of the OS for the A9home prevented the running of software without an AIF header (in accord with Application Note 295) to stop "trashing the desktop".