PHP on IIS doesn't load sqlsrv extension - php

Question

I'm trying to put together a page that can submit data from a form to an MSSQL database via PHP. I've got PHP installed successfully (phpinfo() runs fine even on a remote computer) but it will not load the sqlsrv extension. I know that I'm editing the right php.ini file because I have another extension added (wincache) and it is loading fine, confirmed with both phpinfo() and get_loaded_extensions().
The logs aren't telling me anything. PHP Manager on IIS is telling me that the sqlsrv extension files are enabled. I've restarted the website, the server, and the computer, and nothing's working.
I'm using PHP 7.1.1 on a Windows 7 Ultimate machine. It's running in x64 mode, Non-Thread Safe. I've made sure that the extension files I enabled are the x64, non-thread-safe ones. I don't know what else to check or what more info I need to provide.
EDIT: I ran php-cgi.exe as this page suggested, and it came out with the error mesages:
[31-Mar-2017 22:38:12 UTC] PHP Warning: PHP Startup: Unable to load dynamic library 'C:\Program Files\iis express\PHP\v7.1\ext\php_sqlsrv_7_nts_x64.dll' - The specified procedure could not be found.
in Unknown on line 0
[31-Mar-2017 22:38:17 UTC] PHP Warning: PHP Startup: Unable to load dynamic library 'C:\Program Files\iis express\PHP\v7.1\ext\php_pdo_sqlsrv_7_nts_x64.dll' - The specified procedure could not be found.
in Unknown on line 0
Does this mean that the problem is in the extension DLLs themselves? How would I even go about fixing that?
EDIT 2: ImClarky nailed the problem in that I was apparently using a way outdated version of the extension. I've got it working, but now my authentication is failing for reasons I don't understand:
function connect_sql() {
/* Specify server and connection attributes */
$serverName = "(local)";
/* Get UID and PWD from app-specific files */
$uid = file_get_contents("C:\AppData\uid.txt");
$pwd = file_get_contents("C:\AppData\pwd.txt");
$connectionInfo = array("UID" => $uid,
"PWD" => $pwd,
"Database" => "database_name");
/* Connect using SQL Server Auth */
$conn = sqlsrv_connect($serverName, $connectionInfo);
if ($conn === false)
{
echo "Unable to connect.</br>";
//die(print_r(sqlsrv_errors(), true));
die(print_errors());
}
else {
echo "Connection Successful";
}
/* Free connection resources */
sqlsrv_close($conn);
}
I've double checked that I am using the correct username and password, and I even went in and created an entirely new login using the exact UID and password I'm trying. I still get the following error message every time:
Unable to connect.
SQLSTATE: 28000
code: 18456
message: [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]Login failed for user 'username'.
SQLSTATE: 28000
code: 18456
message: [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]Login failed for user 'username'.

Answer 1

Make sure you add .dll file for extension folder used by php.ini
Also chose correct driver of SQLSRv matched your running PHP
SQLSRv sqlsrv from official microsoft page