I've installed Uniform Server XIV which comes with PHP7.4.  I need to switch to PHP7.3 but the option is greyed out.  I downloaded the 7.3 binaries, named the folder php73 to a address that issue. However Apache is not happy and won't run.  Are there additional steps I need to take?

PS: I did notice

1) The php.ini files needed renaming.

2) Added this line to php.ini extension_dir = "${US_ROOTF}/core/php73/extensions"

3) Renamed the 'ext' folder under PHP73 to 'extensions'  

but that didn't help. BTW nothing in the apache logs.

I resolved this. The approach was all wrong. The correct method is to use the plugin which is located here https://sourceforge.net/projects/miniserver/files/Uniform Server ZeroXIV/ZeroXIV Modules/

There reason I tried to use the binaries was because I was not able to find the plugins. Hopefully this will help someone else find them.