diff --git a/README.md b/README.md
index a5c618f9..6157fea9 100644
--- a/README.md
+++ b/README.md
@@ -212,5 +212,6 @@ the Wine prefix. Removing the option will revert to the previous behavior.
 | <tt>nod3d10</tt>      | <tt>PROTON_NO_D3D10</tt>       | Disable <tt>d3d10.dll</tt> and <tt>dxgi.dll</tt>, for d3d10 games which can fall back to and run better with d3d9. |
 | <tt>noesync</tt>      | <tt>PROTON_NO_ESYNC</tt>       | Do not use eventfd-based in-process synchronization primitives. |
 | <tt>forcelgadd</tt>   | <tt>PROTON_FORCE_LARGE_ADDRESS_AWARE</tt> | Force Wine to enable the LARGE_ADDRESS_AWARE flag for all executables. |
+| <tt>oldglstr</tt>     | <tt>PROTON_OLD_GL_STRING</tt>  | Set some driver overrides to limit the length of the GL extension string, for old games that crash on very long extension strings. |
 
 <!-- Target:  GitHub Flavor Markdown.  To test locally:  pandoc -f markdown_github -t html README.md  -->
diff --git a/proton b/proton
index ea67fcaf..00fe94ea 100755
--- a/proton
+++ b/proton
@@ -222,10 +222,17 @@ check_environment("PROTON_NO_D3D11", "nod3d11")
 check_environment("PROTON_NO_D3D10", "nod3d10")
 check_environment("PROTON_NO_ESYNC", "noesync")
 check_environment("PROTON_FORCE_LARGE_ADDRESS_AWARE", "forcelgadd")
+check_environment("PROTON_OLD_GL_STRING", "oldglstr")
 
 if not "noesync" in config_opts:
     env["WINEESYNC"] = "1"
 
+if "oldglstr" in config_opts:
+    #mesa override
+    env["MESA_EXTENSION_MAX_YEAR"] = "2003"
+    #nvidia override
+    env["__GL_ExtensionStringVersion"] = "17700"
+
 if "forcelgadd" in config_opts:
     #forcelgadd should be used just for testing whether a game is helped by
     #setting LARGE_ADDRESS_AWARE. If it does, then add an AppDefault in the