Small problem with forge 1.11.2

[Justmatt]

Hi ! 

i just downloaded Forge 1.11.2, i installed it in minecraft, from here, no problems. but when i launch Forge in minecraft, theres a weird message that appears.

It kept appearing and i couldnt play minecraft because of that.I tried to download the .jar launcher, i deleted the 1.11.2 version that i installed with the .win installer, and replaced it. But then, this message another time. 

It said that (its in french sorry)

Échec du téléchargement du fichier, le contenu du fichier est différent de celui attendu.
Nom : jopt-simple-4.6.jar
Lien : https://libraries.minecraft.net/net/sf/jopt-simple/jopt-simple/4.6/jopt-simple-4.6.jar
Nom du fichier sur le disque : jopt-simple-4.6.jar
Chemin d'accès : C:\Users\Mat\AppData\Roaming\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.6\jopt-simple-4.6.jar
Existe : File

[Ugdhar]

1.11.2 is no longer supported on these forums due to age.

Please update to a modern version to receive support.

 

See the LTS link at the top of every page for more information.