diff --git a/enrol/lti/ims-blti/OAuth.php b/enrol/lti/ims-blti/OAuth.php
index afd0f74510d..c1d00f594a0 100644
--- a/enrol/lti/ims-blti/OAuth.php
+++ b/enrol/lti/ims-blti/OAuth.php
@@ -148,8 +148,11 @@ class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
     // Sign using the key
     $ok = openssl_sign($base_string, $signature, $privatekeyid);
 
-    // Release the key resource
-    openssl_free_key($privatekeyid);
+    // TODO: Remove this block once PHP 8.0 becomes required.
+    if (PHP_MAJOR_VERSION < 8) {
+      // Release the key resource
+      openssl_free_key($privatekeyid);
+    }
 
     return base64_encode($signature);
   }
@@ -168,8 +171,11 @@ class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
     // Check the computed signature against the one passed in the query
     $ok = openssl_verify($base_string, $decoded_sig, $publickeyid);
 
-    // Release the key resource
-    openssl_free_key($publickeyid);
+    // TODO: Remove this block once PHP 8.0 becomes required.
+    if (PHP_MAJOR_VERSION < 8) {
+      // Release the key resource
+      openssl_free_key($publickeyid);
+    }
 
     return $ok == 1;
   }
diff --git a/enrol/lti/ims-blti/moodle_readme.txt b/enrol/lti/ims-blti/moodle_readme.txt
index 1b8890cd0c7..debb489c38f 100644
--- a/enrol/lti/ims-blti/moodle_readme.txt
+++ b/enrol/lti/ims-blti/moodle_readme.txt
@@ -3,4 +3,5 @@ current code was taken from https://github.com/jfederico/ims-dev/tree/master/bas
 several changes to the code (including bug fixes). As the library is no longer supported upgrades are not possible.
 In future releases we should look into using a supported library.
 
-2021-01-05 - Removed get_magic_quotes_gpc() use, was returning false since ages ago.
+2022-01-05 - MDL-73502 - Removed get_magic_quotes_gpc() use, was returning false since ages ago.
+2022-01-20 - MDL-73523 - Conditional openssl_free_key() use, deprecated by PHP 8.0
diff --git a/lib/google/readme_moodle.txt b/lib/google/readme_moodle.txt
index 5aae6a3631f..e8f736f52aa 100644
--- a/lib/google/readme_moodle.txt
+++ b/lib/google/readme_moodle.txt
@@ -40,7 +40,9 @@ Local changes (to reapply until upstream upgrades contain them):
     * MDL-67034 php74 compliance fixes
     * MDL-67115 php74 implode() compliance fixes. This is fixed in upstream library v2.2.4
       (verify that https://github.com/googleapis/google-api-php-client/pull/1683 is applied)
-
+    * MDL-73523 php80 compliance. openssl_xxx_free() methods deprecated. I've been unable to
+      find any issue upstream and the current library versions are way different from the ones
+      we are using here.
 
 Information
 -----------
diff --git a/lib/google/src/Google/Signer/P12.php b/lib/google/src/Google/Signer/P12.php
index 1fbed87a825..6e9cbff2dea 100644
--- a/lib/google/src/Google/Signer/P12.php
+++ b/lib/google/src/Google/Signer/P12.php
@@ -74,7 +74,10 @@ class Google_Signer_P12 extends Google_Signer_Abstract
   public function __destruct()
   {
     if ($this->privateKey) {
-      openssl_pkey_free($this->privateKey);
+      // TODO: Remove this block once PHP 8.0 becomes required.
+      if (PHP_MAJOR_VERSION < 8) {
+        openssl_pkey_free($this->privateKey);
+      }
     }
   }
 
diff --git a/lib/google/src/Google/Verifier/Pem.php b/lib/google/src/Google/Verifier/Pem.php
index 3d6e0fd2d59..25e3ef2dbfd 100644
--- a/lib/google/src/Google/Verifier/Pem.php
+++ b/lib/google/src/Google/Verifier/Pem.php
@@ -50,7 +50,10 @@ class Google_Verifier_Pem extends Google_Verifier_Abstract
   public function __destruct()
   {
     if ($this->publicKey) {
-      openssl_x509_free($this->publicKey);
+      // TODO: Remove this block once PHP 8.0 becomes required.
+      if (PHP_MAJOR_VERSION < 8) {
+          openssl_x509_free($this->publicKey);
+      }
     }
   }
 
diff --git a/mnet/lib.php b/mnet/lib.php
index c6c8209d021..e62fd865e94 100644
--- a/mnet/lib.php
+++ b/mnet/lib.php
@@ -422,7 +422,10 @@ function mnet_generate_keypair($dn = null, $days=28) {
 
     // We export our self-signed certificate to a string.
     openssl_x509_export($selfSignedCert, $keypair['certificate']);
-    openssl_x509_free($selfSignedCert);
+    // TODO: Remove this block once PHP 8.0 becomes required.
+    if (PHP_MAJOR_VERSION < 8) {
+        openssl_x509_free($selfSignedCert);
+    }
 
     // Export your public/private key pair as a PEM encoded string. You
     // can protect it with an optional passphrase if you wish.
@@ -431,7 +434,10 @@ function mnet_generate_keypair($dn = null, $days=28) {
     } else {
         $export = openssl_pkey_export($new_key, $keypair['keypair_PEM'] /* , $passphrase */);
     }
-    openssl_pkey_free($new_key);
+    // TODO: Remove this block once PHP 8.0 becomes required.
+    if (PHP_MAJOR_VERSION < 8) {
+        openssl_pkey_free($new_key);
+    }
     unset($new_key); // Free up the resource
 
     return $keypair;
diff --git a/mod/lti/OAuth.php b/mod/lti/OAuth.php
index 0790c4c5dca..dde625452a3 100644
--- a/mod/lti/OAuth.php
+++ b/mod/lti/OAuth.php
@@ -262,8 +262,11 @@ class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
         // Sign using the key
         $ok = openssl_sign($base_string, $signature, $privatekeyid);
 
-        // Release the key resource
-        openssl_free_key($privatekeyid);
+        // TODO: Remove this block once PHP 8.0 becomes required.
+        if (PHP_MAJOR_VERSION < 8) {
+            // Release the key resource
+            openssl_free_key($privatekeyid);
+        }
 
         return base64_encode($signature);
     }
@@ -282,8 +285,11 @@ class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
         // Check the computed signature against the one passed in the query
         $ok = openssl_verify($base_string, $decoded_sig, $publickeyid);
 
-        // Release the key resource
-        openssl_free_key($publickeyid);
+        // TODO: Remove this block once PHP 8.0 becomes required.
+        if (PHP_MAJOR_VERSION < 8) {
+            // Release the key resource
+            openssl_free_key($publickeyid);
+        }
 
         return $ok == 1;
     }
@@ -897,4 +903,4 @@ class OAuthUtil {
         // Each name-value pair is separated by an '&' character (ASCII code 38)
         return implode('&', $pairs);
     }
-}
\ No newline at end of file
+}
diff --git a/repository/s3/README_MOODLE.txt b/repository/s3/README_MOODLE.txt
index de664ce03a3..3d60492f977 100644
--- a/repository/s3/README_MOODLE.txt
+++ b/repository/s3/README_MOODLE.txt
@@ -12,3 +12,4 @@ Local changes applied:
 upstream. Remove the local changes if so)
 
 MDL-67031 php74 compliance. Change curly to square braces.
+MDL-73523 php80 compliance. Deprecated openssl_free_key() use (https://github.com/tpyo/amazon-s3-php-class/issues/178)
diff --git a/repository/s3/S3.php b/repository/s3/S3.php
index 631aba3719e..7cca16248da 100644
--- a/repository/s3/S3.php
+++ b/repository/s3/S3.php
@@ -351,7 +351,13 @@ class S3
 	public static function freeSigningKey()
 	{
 		if (self::$__signingKeyResource !== false)
-			openssl_free_key(self::$__signingKeyResource);
+		{
+			// TODO: Remove this block once PHP 8.0 becomes required.
+			if (PHP_MAJOR_VERSION < 8) {
+				openssl_free_key(self::$__signingKeyResource);
+			}
+			self::$__signingKeyResource = null;
+		}
 	}