Upgrade Aegir platform with Drupal core update

Aegir doesn't have any automatic way to upgrade Platform, but it can be done using Drush and a script.

(The below guide is for updating Drupal core only, leaving leaving the modules from the previous version)

su aegir
cd /var/aegir/platforms/
drush dl drupal-7.52
Log in to Aegir and Create new platform, verify
rsync -av <current_platform>/sites/ <new_platform>/sites
cd <new_platform>/sites
rm -r <site1 site2 site3 ...> (clear all of the sites)
cd all
chown -R aegir:aegir modules (just to make sure)
verify this platform again (to load oll of the copied modules)
Log in Aegir and migrate the sites to the new core!