1. Manual installation on any suPHP server only.
2. Remove inserts from oc_authtoken, oc_filecache, oc_file_locks, oc_circles_circle, oc_circles_member it gets created after login
3. "1|" is added in hashed password in "lib\private\security\hasher.php". In case password changes check "1" constant from this file.
4. Delete "appdata_********" folder from data directory, it gets created after login
5. Delete "configvalue" for 'scss.variables' or "theming.variables" in `oc_appconfig` table as it generates itself on visiting. (Since 12.0.0)
6. Check and move apps/bruteforcesettings from manual to zip and to cross check compare with https://github.com/nextcloud/bruteforcesettings (check in every version and move accordingly)
7. Always check https://docs.nextcloud.com/server/21/admin_manual/maintenance/manual_upgrade.html in major versions and set "$allowed_ver" accordingly in upgrade.php
8. PHP REQUIREMENT LINK: https://docs.nextcloud.com/server/21/admin_manual/installation/source_installation.html#prerequisites-for-manual-installation
9. We have added "admin_email" in "oc_preferences" table since 16.0.4. ( In Forget password it asks for Email ID ).
10. Take database dump while First run wizard page is loaded(i.e before the dashboard page is loaded). Taking dump on dashboard page would add the entry '('[[admin_username]]', 'firstrunwizard', 'show', '0')' in oc_preferences table which would disable the run wizard.
11. We have set PHP requirement to 7.2 because manual installation doesn't start on PHP 7.1. Also, they have mentioned on their installer that PHP 7.2 is required.
12. Uncheck "install recommended apps" option in manual installation.
13. Changelog : https://nextcloud.com/changelog/
14. PRIMARY keys are not generated while upgrading to 20.0.2, to generate these keys manually, user can run following command. sudo -u [[USER]] [[PATH to PHP]] [[SOFTPATH]]/occ db:add-missing-primary-keys