clarify relationship of OsmoGGSN to OpenGGSN.

Change-Id: If0e18fb02a7dcc472f5f5fbfaf53a107382ef7e5
diff --git a/README.md b/README.md
index 42613cf..80126e0 100644
--- a/README.md
+++ b/README.md
@@ -6,8 +6,8 @@
 networks such as GPRS, EDGE, UMTS or HSPA.
 
 OsmoGGSN is part of the [Osmocom](https://osmocom.org/) Open Source
-Mobile Communications projects, even thogh it was previously developed
-by Mondru AB.
+Mobile Communications projects and the successor to OpenGGSN.
+OpenGGSN was developed until 2004 by Mondru AB.
 
 Homepage
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