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docs/src/main/paradox/migration-guide/index.md

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 * If you are currently using an old version of Akka HTTP or Spray, you should first follow the [Akka HTTP migration guide](https://doc.akka.io/docs/akka-http/10.2/migration-guide/index.html)
-* The @extref:[migration guide](pekko-docs:project/migration/index.md) for the core Apache Pekko libs is a useful guideline.
+* The @extref:[migration guide](pekko-docs:project/migration/index.html) for the core Apache Pekko libs is a useful guideline.
 * for Pekko jar dependencies, the groupId is "org.apache.pekko" instead of "com.typesafe.akka"
 * the jar names start with "pekko" instead of "akka" - e.g. pekko-http_2.13.jar instead of akka-http_2.13.jar
 * If you have a dependency akka-http2-support, Pekko does not need a separate jar. The support is built into main pekko-http jars.