diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -25,6 +25,9 @@ Pull requests are more than welcome (see [TODO](https://github.com/android-passw
        height="80" />
 </a>
 
+## Build types
+
+We generate release binaries under two separate configurations titled `free` and `nonFree`. The distinction was created following the merge of [#900](https://msfjarvis.dev/aps/pr/900), that introduced a dependency on closed source GMS libraries. Since F-Droid is a FOSS-only app store, we created the `free` flavor where we do not ship the GMS dependency and thus the feature to fill SMS OTPs is unavailable.
 
 ## Features