diff --git a/src/nix-store/nix-store.cc b/src/nix-store/nix-store.cc
index b854ef1e7..85f142c39 100644
--- a/src/nix-store/nix-store.cc
+++ b/src/nix-store/nix-store.cc
@@ -808,12 +808,15 @@ static void opServe(Strings opFlags, Strings opArgs)
         if (GET_PROTOCOL_MINOR(clientVersion) >= 2)
             settings.maxLogSize = readNum<unsigned long>(in);
         if (GET_PROTOCOL_MINOR(clientVersion) >= 3) {
-            if (readInt(in) != 0) {
+            auto nrRepeats = readInt(in);
+            if (nrRepeats != 0) {
                 throw Error("client requested repeating builds, but this is not currently implemented");
             }
-            if (readInt(in) != 0) {
-                throw Error("client requested enforcing determinism, but this is not currently implemented");
-            }
+            // Ignore. It used to be true by default, but also only never had any effect when `nrRepeats == 0`.
+            // We have already asserted that `nrRepeats` in fact is 0, so we can safely ignore this without
+            // doing something other than what the client asked for.
+            auto _enforceDeterminism = readInt(in);
+
             settings.runDiffHook = true;
         }
         if (GET_PROTOCOL_MINOR(clientVersion) >= 7) {