It has been widely reported that Palm OS 5 would not support hacks due mainly to the way in which the hacks worked within older versions of the Palm OS. PalmSource has enabled 'notification applications' under OS 5, which are basically the same thing as hacks.
TealSoft has released an upgraded version of TealMaster that will allow for certain hacks to run in OS 5. User trials have seen mixed success. Certain hacks will work, and others don't. I am curious as to whether the developes of non-working hacks will choose to re-write the hack to work in OS 5, or if they will simply abandon their hack and write a notification application that accomplishes the same task.