[TASK] Rename enable security setting

Classes/Service/RegisterService.php

@@ -87,7 +87,7 @@ class RegisterService implements \TYPO3\CMS\Core\SingletonInterface {
 		$extensionConfiguration = unserialize($GLOBALS['TYPO3_CONF_VARS']['EXT']['extConf']['sg_mail'], ['array']);
 
 		// @TODO remove in version 5.0.0
-		if (((int) $extensionConfiguration['enableSecurity']) === 0) {
+		if (((int) $extensionConfiguration['supportOldRegistrations']) === 0) {
 			MailTemplateService::registerExtensions();
 		}
 

ext_conf_template.txt

@@ -8,4 +8,4 @@ excludeTemplates =
 templates =
 
 # cat=general; type=boolean; label=LLL:EXT:sg_mail/Resources/Private/Language/locallang.xlf:configuration.enableSecurity
-enableSecurity = 0
+supportOldRegistrations = 0