Upgraded my #Friendica. I used the following script to minimize disruption, which assumes the installation is in /var/www/$SITE, daemon.php rather than worker.php is used and both git repositories are already on the correct branch (e.g. stable):

#!/bin/bash

SITE=friendica.gidikroon.eu
ADDONDIR=addon

sudo -Hu www-data sh -c "cd ~/$SITE \
                         && /usr/bin/php ~/$SITE/bin/daemon.php stop \
                         && git fetch origin \
                         && (cd $ADDONDIR && git fetch origin) \
                         && git merge --ff-only \
                         && (cd $ADDONDIR && git merge --ff-only) \
                         && bin/composer.phar install --no-dev \
                         && /usr/bin/php ~/$SITE/bin/daemon.php start"

The main difference between this and the documented upgrade procedure is splitting the fetch and the merge steps, to avoid having old addons running on a new main in case of a slow network, and doing the composer step with updated addons included. The main purpose of the script is so I don't forget to stop the daemon processes or to update the addons.

When the current branch is a release candidate branch, but the release has happened and I want to switch to stable, I use this script to avoid jumping back to the previous release during the process:

#!/bin/bash

SITE=friendica-dev.gidikroon.eu
# For when the current branch is a release candidate and the actual release has just been released,
# or for when the current branch is 'stable' and a release candidate has been branched off.
NEWBRANCH=stable
ADDONDIR=addon

sudo -Hu www-data sh -c "cd ~/$SITE \
                         && /usr/bin/php ~/$SITE/bin/daemon.php stop \
                         && git fetch origin $NEWBRANCH:$NEWBRANCH \
                         && (cd $ADDONDIR && git fetch origin $NEWBRANCH:$NEWBRANCH) \
                         && git switch $NEWBRANCH \
                         && (cd $ADDONDIR && git switch $NEWBRANCH) \
                         && bin/composer.phar install --no-dev \
                         && /usr/bin/php ~/$SITE/bin/daemon.php start"

A very similar script I used for Osada and Zap, assuming its repositories are already on the target branches (e.g. release):

#!/bin/bash

SITE=osada.gidikroon.eu
ADDONDIR=extend/addon/zaddons

sudo -Hu www-data sh -c "cd ~/$SITE \
                         && git fetch origin \
                         && (cd $ADDONDIR && git fetch origin) \
                         && git merge --ff-only \
                         && (cd $ADDONDIR && git merge --ff-only) \
                         && composer install --no-dev"