After carrying out a TYPO3 update, it is not enough to simply call up the frontend and check "if everything is working". If you d like to avoid security gaps, Google penalties, 404 errors, a deterioration of the user experience or even "lost" requests/orders, you should definitely carry out the following tests.
Check in the Installtool whether there are still error messages. You can reach the Installtool at:
<mywebsite>/typo3/install
.
This requires a password that you can reset with ftp access (more info on changing the Installtool password here).
As of TYPO3 v9, you can do this directly from the TYPO3 backend - provided you are an admin and have the so-called "maintainer" rights. See the section "Admin tools" in the module bar.
Go through the individual points under "Upgrade".
When performing a TYPO3 update, developers usually have to set the system to debug mode. Unfortunately, they often forget to switch back to live mode. This makes the website very slow and more vulnerable in terms of security (as system information can be output).
Debug mode is checked/set in the install tool under Settings -> Configuration Presets -> Debug Settings.
The status report shows possible system errors (outdated TYPO3 version, wrong database format, SOLR problems, etc.). While messages with a yellow background are to be understood as warnings, you should immediately follow up and eliminate red messages.
You can get the status report in the TYPO3 backend in the module spate (far left) under System -> Reports
The log can also be displayed in the module column "SYSTEM" of the TYPO3 backend. Various system messages (logins/actions/errors) are logged here.
View the list of all errors ("Action: Error") since the update.
RewriteCond %{SERVER_PORT} !^443$
RewriteCond %{HTTP_HOST} ^www\.beispiel\.de$ [NC]
RewriteRule (.*) https://www.beispiel.de/$1 [R=301,L]
You can find out more about TYPO3 upgrades here.