I wonder for how long the unit will be supported. Especially I want to understand for how long I can expect software updates, e.g., for Mac OS. Hence, I don't want to run the risk of not beeing able to use the unit 2 years from now.
I cannot predict the future, but Promise has been updating firmware for Pegasus models long EOL and the drivers and Utilities are mostly backward compatible (the Pegasus Pro utility has limited backwards compatibility).
For the long EOL Pegasus 2 the firmware was updated in 2020.
From the older units, e.g. R2, I have read mixed feedback ranging from some users claming they can no longer use they're units with newer (M1/M2) Macs to others who are able to still use these units without problems.
The Pegasus 2 works fine with the latest MACs, as does the Pegasus 1.
The problem is some people use the driver or the Promise Utility from the Pegasus2 download section and they are not forward compatible with the latest macOS. Promise has both kernel space and user space drivers (Apple has updated their driver model for greater security) for the latest macOS.
The firmware needs to be from the Pegasus2 downloads page, but the Utility and driver should be from the Pegasus32 downloads, they are backwards compatible with the Pegasus 2.
Here is what you need.
First, the firmware should be updated to the latest version listed above.
We also have a Knowledge Base article on updating the firmware on the Pegasus1 and Pegasus 2.
For the Pegasus1/2 this is the Promise Utility that should be used (v4.06.0000.01). Later versions will fail to update Pegasus 2 firmware.
For the driver we recommend the user space driver for M1 MACs.
For Intel MACs, we recommend the kernel space driver.
There is a PDF in the dmg explaining how to update the driver.
These issues are discussed often in the forum, if a user is having difficulty please ask them to post here.