I followed (more or less) Instruction.
0. I created a new subdomain
- copied data folder, .hataccess, Plugins folder and config.php from KANBOARD installation to my HDD
- Unzipped 1.2.24 on my HDD
- Transferred (ftp) to new sub domain as new KANBOARD 1.2.24 installation
- Copied contents from (1) to KANBOARD 1.2.24 installation
- Did some basic tests with KANBOARD 1.2.24 installation, saw all myprojects and so on, seemed fine
- Renamed 1.2.22 folder to somethin else
- renamed new subdomain folder with 1.2.24 to old subdomain name
- renamed “somethin else” folder to new subdomain.
Now I reach the same KANBOARD contents
- via normal subdomain as 1.2.24 KANBOARD
- via new subdomain as 1.2.23 KANBOARD