Cannot install

[AxelDuerrbaum]

Hello,

I cannot install a new version of Webcalendar (git clone from today == v1.9.12)

System is Debian bookworm/php.2/mariadb 10.5, database"webcalendar" is dropped
database type is mysqli.

During the installation I get stuck at step /webcalendar/install/index.php?action=createdb

I get alwas the error:
PHP Fatal error: Uncaught Error: Call to a member function real_escape_string() on bool in /opt/WWW/webcalendar/includes/dbi4php.php:712\nStack trace:\n#0 /opt/WWW/webcalendar/includes/dbi4php.php(757): dbi_escape_string()\n#1 /opt/WWW/webcalendar/install/install_functions.php(46): dbi_execute()\n#2 /opt/WWW/webcalendar/install/index.php(309): getDbVersion()\n#3 {main}\n thrown in /opt/WWW/webcalendar/includes/dbi4php.php on line 712, referer:.../webcalendar/install/index.php?action=dbsettings

The string in real_escape_string in dbi4php:712 is "WEBCAL_PROGRAM_VERSION", not "v1.9.12"