Update SECURITY.md

Author: matidau

SECURITY.md

@@ -7,12 +7,12 @@ The following versions are currently supported for security patches:
 | Version | Supported          |
 | ------- | ------------------ |
 | 2.7.x   | :white_check_mark: |
-| 2.6.x   | :white_check_mark: |
-| < 2.6   | :x:                |
+| < 2.7   | :x:                |
 
 ## Reporting a Vulnerability
 
 Please report (suspected) security vulnerabilities at 
 https://github.com/Z-Hub/Z-Push/discussions. You will receive a response from 
 us within 48 hours. If the issue is confirmed, we will release a patch as soon 
 as possible depending on complexity.
+