diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index bc528140b..784c12b16 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -640,8 +640,10 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
                 if (i->value->type == tNull) continue;
             }
 
-            if (i->name == state.sContentAddressed)
+            if (i->name == state.sContentAddressed) {
+                settings.requireExperimentalFeature("ca-derivations");
                 contentAddressed = state.forceBool(*i->value, pos);
+            }
 
             /* The `args' attribute is special: it supplies the
                command-line arguments to the builder. */
diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index c88bb3c6d..6a12e8734 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -163,12 +163,13 @@ static DerivationOutput parseDerivationOutput(const Store & store, std::istrings
                       },
                   }
                }
-            : DerivationOutput {
-                  .output = DerivationOutputFloating {
+            : (settings.requireExperimentalFeature("ca-derivations"),
+              DerivationOutput {
+                  .output =  DerivationOutputFloating {
                       .method = std::move(method),
                       .hashType = std::move(hashType),
                   },
-              };
+              });
     } else
         return DerivationOutput {
             .output = DerivationOutputInputAddressed {
@@ -559,12 +560,13 @@ static DerivationOutput readDerivationOutput(Source & in, const Store & store)
                       },
                   }
                }
-            : DerivationOutput {
+            : (settings.requireExperimentalFeature("ca-derivations"),
+              DerivationOutput {
                   .output = DerivationOutputFloating {
                       .method = std::move(method),
                       .hashType = std::move(hashType),
                   },
-              };
+              });
     } else
         return DerivationOutput {
             .output = DerivationOutputInputAddressed {