I have migrated one of my Tikis from my personal webspace to one of an organization for which I admin the IT, and therefore I did have a look at the installer (but edited db/local.php instead).
The installer throws several warnings, that might will become errors in the next PHP versions. This is what you get on PHP 7.4:
Deprecated: Array and string offset access syntax with curly braces is deprecated in /homepages/0/MYHOME/htdocs/tiki-18.8/lib/init/initlib.php on line 221 Deprecated: Array and string offset access syntax with curly braces is deprecated in /homepages/0/MYHOME/htdocs/tiki-18.8/vendor_bundled/vendor/h5p/h5p-core/h5p.classes.php on line 2590 Deprecated: Array and string offset access syntax with curly braces is deprecated in /homepages/0/MYHOME/htdocs/tiki-18.8/vendor_bundled/vendor/h5p/h5p-core/h5p-development.class.php on line 70 Deprecated: Array and string offset access syntax with curly braces is deprecated in /homepages/0/MYHOME/htdocs/tiki-18.8/lib/tikilib.php on line 414 Deprecated: Array and string offset access syntax with curly braces is deprecated in /homepages/0/MYHOME/htdocs/tiki-18.8/lib/tikilib.php on line 1858 Deprecated: Array and string offset access syntax with curly braces is deprecated in /homepages/0/MYHOME/htdocs/tiki-18.8/lib/tikilib.php on line 4483 Deprecated: Array and string offset access syntax with curly braces is deprecated in /homepages/0/MYHOME/htdocs/tiki-18.8/lib/tikilib.php on line 4483 Deprecated: Array and string offset access syntax with curly braces is deprecated in /homepages/0/MYHOME/htdocs/tiki-18.8/lib/tikilib.php on line 5779