First, I want to apologize in case my post is in the wrong place. My origin is not IT / coding, but the business. Therefore my questions might seem silly to the cracks of you.
I have an issue with version 1.9.19 (bitnami stack in azure cloud), which apparantly is fixed with 1.9.19.01.
According to the installation manual, I would just need to follow these steps:
Unfortunately, this does not work4.1.1. Code upgrade only
This upgrade is common for bug-fixing releases or release candidates. Maintenance (Bug fixing) release is for example 1.6.0 -> 1.6.1. Database schema shouldn't changed in this case.
Please, follow the next steps:
•Backup all files of the previous version in testlink directory and database.
•Remove the all files from directory.
•Copy a new version to the same directory.
•Copy config_db.inc.php and custom_config.inc.php file to the new structure and modify other configuration parameters and changes according your previous settings (for example in config.inc.php file).
•Now, it should work.

When trying to log in, I get this message:
Info icon
The website cannot display the page HTTP 500
Most likely causes:
•The website is under maintenance.
•The website has a programming error.
What you can try:
Refresh the page.
Go back to the previous page.
I then reverted the changes and only replaced the 23 changed files (found the files here: https://github.com/TestLinkOpenSourceTR ... ff=unified
But this also does not seem to work (now I can log in, but most of the pages display without any content).
Can please somebody advise?
Thank you very much!
Chris
*********************** Edit **************************
For the step: "•Remove the all files from directory.", I removed all files from this directory and placed the new files also into this directory:
/opt/bitnami/apps/testlink/htdocs