Capturing post data from C++ application in Codeigniter 4

OK, so - I know I commented these lines in .htaccess the other day and it made no difference...
   

Code:

# Redirect Trailing Slashes...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_URI} (.+)/$
    RewriteRule ^ %1 [L,R=301]

so either I made the change and neglected to push it to the server OR there was a caching issue, because I tried again this morning, and lo and behold, I get the proper response:

CI4 - original .htaccess

Code:

Array
(
    [REDIRECT_UNIQUE_ID] => Yo5S1RURL_PRU7907pX_7gAAAAU
    [REDIRECT_SCRIPT_URL] => /verification/activation
    [REDIRECT_SCRIPT_URI] => http://test.mysite.com/verification/activation
    [REDIRECT_STATUS] => 200
    [UNIQUE_ID] => Yo5S1RURL_PRU7907pX_7gAAAAU
    [SCRIPT_URL] => /verification/activation
    [SCRIPT_URI] => http://test.mysite.com/verification/activation
    [HTTP_AUTHORIZATION] => Basic XXXXXXXXXXXXXXXXXXXXX
    [HTTP_HOST] => test.mysite.com
    [HTTP_CACHE_CONTROL] => no-cache
    [HTTP_COOKIE] => ci_session418=in9nd1155tk5qvf72u8dp914sm1vhnjb; ci_session=f4g49781l5503dprd6l9kp5uk4k7msb8
    [HTTP_USER_AGENT] => SubscriptionCheck
    [HTTP_X_FORWARDED_FOR] => 96.68.149.126
    [HTTP_X_FORWARDED_PORT] => 443
    [HTTP_X_FORWARDED_PROTO] => https
    [HTTP_CONNECTION] => keep-alive
    [PATH] => /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
    [SERVER_SIGNATURE] =>
    [SERVER_SOFTWARE] => Apache/2.4.53 () PHP/7.4.28
    [SERVER_NAME] => test.mysite.com
    [SERVER_ADDR] => 172.30.1.69
    [SERVER_PORT] => 80
    [REMOTE_ADDR] => 172.30.4.42
    [DOCUMENT_ROOT] => /var/www/public
    [REQUEST_SCHEME] => http
    [CONTEXT_PREFIX] =>
    [CONTEXT_DOCUMENT_ROOT] => /var/www/public
    [SERVER_ADMIN] => root@localhost
    [SCRIPT_FILENAME] => /var/www/public/index.php
    [REMOTE_PORT] => 40424
    [REMOTE_USER] => MyUser
    [AUTH_TYPE] => Basic
    [REDIRECT_URL] => /verification/activation
    [GATEWAY_INTERFACE] => CGI/1.1
    [SERVER_PROTOCOL] => HTTP/1.1
    [REQUEST_METHOD] => GET
    [QUERY_STRING] =>
    [REQUEST_URI] => /verification/activation
    [SCRIPT_NAME] => /index.php
    [PATH_INFO] => /verification/activation
    [PATH_TRANSLATED] => redirect:/index.php/verification/activation/activation
    [PHP_SELF] => /index.php/verification/activation
    [PHP_AUTH_USER] => MyUser
    [PHP_AUTH_PW] => MyPassword
    [REQUEST_TIME_FLOAT] => 1653494485.0647
    [REQUEST_TIME] => 1653494485
    [CI_ENVIRONMENT] => development
)

RESULTS:
Subscription number:
Activation: No
Error: No parameters sent.


CI4 - Removed # Redirect Trailing Slashes... directives in .htaccess

Code:

Array
(
    [REDIRECT_UNIQUE_ID] => Yo5XSGhqtIeAir6UX6zOqwAAAAg
    [REDIRECT_SCRIPT_URL] => /verification/activation/
    [REDIRECT_SCRIPT_URI] => http://test.mysite.com/verification/activation/
    [REDIRECT_STATUS] => 200
    [UNIQUE_ID] => Yo5XSGhqtIeAir6UX6zOqwAAAAg
    [SCRIPT_URL] => /verification/activation/
    [SCRIPT_URI] => http://test.mysite.com/verification/activation/
    [HTTP_AUTHORIZATION] => Basic XXXXXXXXXXXXXXXXXXXXX
    [HTTP_HOST] => test.mysite.com
    [HTTP_CACHE_CONTROL] => no-cache
    [CONTENT_TYPE] => application/x-www-form-urlencoded
    [HTTP_COOKIE] => ci_session418=fbmt81ebsdc0bimcha0sjgmp7mpahaqf; ci_session=dodrcv30dilioko3m15ttu0p7acgpeaq
    [HTTP_USER_AGENT] => SubscriptionCheck
    [HTTP_X_FORWARDED_FOR] => 96.68.149.126
    [HTTP_X_FORWARDED_PORT] => 443
    [HTTP_X_FORWARDED_PROTO] => https
    [CONTENT_LENGTH] => 170
    [HTTP_CONNECTION] => keep-alive
    [PATH] => /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
    [SERVER_SIGNATURE] =>
    [SERVER_SOFTWARE] => Apache/2.4.53 () PHP/7.4.28
    [SERVER_NAME] => test.mysite.com
    [SERVER_ADDR] => 172.30.1.69
    [SERVER_PORT] => 80
    [REMOTE_ADDR] => 172.30.4.42
    [DOCUMENT_ROOT] => /var/www/public
    [REQUEST_SCHEME] => http
    [CONTEXT_PREFIX] =>
    [CONTEXT_DOCUMENT_ROOT] => /var/www/public
    [SERVER_ADMIN] => root@localhost
    [SCRIPT_FILENAME] => /var/www/public/index.php
    [REMOTE_PORT] => 41564
    [REMOTE_USER] => MyUser
    [AUTH_TYPE] => Basic
    [REDIRECT_URL] => /verification/activation/
    [GATEWAY_INTERFACE] => CGI/1.1
    [SERVER_PROTOCOL] => HTTP/1.1
    [REQUEST_METHOD] => POST
    [QUERY_STRING] =>
    [REQUEST_URI] => /verification/activation/
    [SCRIPT_NAME] => /index.php
    [PATH_INFO] => /verification/activation/
    [PATH_TRANSLATED] => redirect:/index.php/verification/activation//activation/
    [PHP_SELF] => /index.php/verification/activation/
    [PHP_AUTH_USER] => MyUser
    [PHP_AUTH_PW] => MyPassword
    [REQUEST_TIME_FLOAT] => 1653495624.0889
    [REQUEST_TIME] => 1653495624
    [CI_ENVIRONMENT] => development
)

RESULTS:
Subscription number: 9999999999999999
Activation: No
Error: Activation Key does not exist.

Thank you to all who responded. But now my question is, how will it affect the Codeigniter base if those lines are removed from the .htaccess file? First passes seem to indicate that it all still works just fine, but.... what issues might arise?