Update README.md

Author: XWB

README.md

@@ -36,7 +36,7 @@ The following table shows the compatibilities of different versions of the bundl
 | FOSElasticaBundle                                                                       | Elastica | Elasticsearch | Symfony    | PHP   |
 | --------------------------------------------------------------------------------------- | ---------| ------------- | ---------- | ----- |
 | [6.4] (master)                                                                          | ^7.1     | 7.\*          | ^5.4\|^6.4\|^7.0 | ^7.4\|^8.0 |
-| [5.1] (5.1.x)                                                                           | ^5.3\|^6 | 5.\*\|6.\*    | ^3.4\|^4   | >=7.1 |
+| [5.1] (unmaintained)                                                                    | ^5.3\|^6 | 5.\*\|6.\*    | ^3.4\|^4   | >=7.1 |
 | [5.0] (unmaintained)                                                                    | ^5.2\|^6 | 5.\*\|6.\*    | ^3.2\|^4   | >=5.6 |
 | [4.x] (unmaintained)                                                                    | 3.2.\*   | 2.\*          | ^2.8\|^3.2 | >=5.5 |
 | [3.2.x] (unmaintained)                                                                  | ^2.1     | 1.\*          | ^2.3\|^3   | >=5.3 |