found 803232 1.1.0-2.1 reopen 803232 thanks Well, this is not fixed :/
I think the problem comes from the is_irqbalance_enabled() function in the config script.
In the case of the upgrade when running systemd, we cannot trust systemctl is-enabled to make any decisions as the .service file has never been enabled. We need to rely on the state of the LSB scripts during the upgrade to know what to do.
I was thinking about this change to test if the script is enabled in any runlevel:
diff -Nru irqbalance-1.1.0/debian/irqbalance.config irqbalance-1.1.0/debian/irqbalance.config --- irqbalance-1.1.0/debian/irqbalance.config 2016-12-30 21:54:18.000000000 +0100 +++ irqbalance-1.1.0/debian/irqbalance.config 2016-12-31 01:49:20.000000000 +0100 @@ -37,7 +37,7 @@ # will be switched to update-rc.d handling in postinst... if [ "$ENABLED" = "0" ]; then db_set irqbalance/enable false - elif [ -e $UPGRADE_FLAG_FILE ] && ! is_irqbalance_enabled; then + elif [ -e $UPGRADE_FLAG_FILE ] && ! ls /etc/rc*.d/S*irqbalance >/dev/null 2>&1; then db_set irqbalance/enable false elif [ ! -e $INSTALL_FLAG_FILE ] && [ ! -e $UPGRADE_FLAG_FILE ]; then # dpkg-reconfigure