I am happy to see that there will be at least one more update before OS4.2 is released.
Update 1 was an ISO image. I had no problems creating a CD-R, but there was an issue with some drivers that caused havoc with the MicroA1 systems. Many of us had to disable two onboard USB ports to allow us to boot into a stable system. I had no problems doing the actual updates for update 2 or update 3. Just as a precaution, I backed up my prefs files, user-startup and a few other important files. Then I downloaded the lha file, used Unarc to unarchive the files and performed the update. All very straight forward.
A few years ago, I moved most of my third part stuff off my system partition and I have kept my system partition as clean as possible in an attempt to avoid extra work when it comes time to upgrade.
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redfox