Update version-targeting.mdx (#639)

docs/faq/targeting/version-targeting.mdx

@@ -10,7 +10,7 @@ Can Nimbus experiments/rollouts target specific beta releases, i.e. can I expres
 ### Answer
 **Yes.** 
 
-If you are a mobile engineer, see steps [here](/faq/mobile-faq) for how to add a version.
+If you are a mobile engineer, see steps [here](/faq/mobile-faq) for how to add a version.  To find how the version numbers work for your platform check https://searchfox.org/mozilla-central/source/mobile/android/docs/shared/versioning.md.
 
 Otherwise, file an issue [here](https://github.com/mozilla/experimenter/issues/new) to add a specific version (of beta, nightly, or release) and then ping in [`#ask-experimenter`](https://mozilla.slack.com/archives/CF94YGE03) on Slack.