I checked with the Start Here file that comes bundled with 8.8.1 and found the following, which indicates that you can continue to use upgrade.sh:
The Installation and Upgrade Assistant tool requires a Java runtime environment. The command line scripts equivalents are in the /scripts directory of the Pega Platform media named: install.bat, install.sh, upgrade.bat, and upgrade.sh.
Here is a full view of the Start Here file:
Posted: 2 weeks ago
Posted: 11 Jan 2023 12:09 EST
HARI LOSARI (HARIL043)