diff --git a/flake.nix b/flake.nix
index e59ec9a35..3e236aaca 100644
--- a/flake.nix
+++ b/flake.nix
@@ -150,6 +150,11 @@
       # 'nix.perl-bindings' packages.
       overlay = final: prev: {
 
+        # An older version of Nix to test against when using the daemon.
+        # Currently using `nixUnstable` as the stable one doesn't respect
+        # `NIX_DAEMON_SOCKET_PATH` which is needed for the tests.
+        mainstream-nix = prev.nixUnstable;
+
         nix = with final; with commonDeps pkgs; stdenv.mkDerivation {
           name = "nix-${version}";
           inherit version;
@@ -158,6 +163,8 @@
 
           VERSION_SUFFIX = versionSuffix;
 
+          OUTER_NIX = mainstream-nix;
+
           outputs = [ "out" "dev" "doc" ];
 
           nativeBuildInputs = nativeBuildDeps;
@@ -486,6 +493,8 @@
         stdenv.mkDerivation {
           name = "nix";
 
+          OUTER_NIX = mainstream-nix;
+
           outputs = [ "out" "dev" "doc" ];
 
           nativeBuildInputs = nativeBuildDeps;
diff --git a/tests/common.sh.in b/tests/common.sh.in
index de44a4da4..277dd6dfa 100644
--- a/tests/common.sh.in
+++ b/tests/common.sh.in
@@ -57,7 +57,6 @@ clearStore() {
     mkdir "$NIX_STORE_DIR"
     rm -rf "$NIX_STATE_DIR"
     mkdir "$NIX_STATE_DIR"
-    nix-store --init
     clearProfiles
 }
 
@@ -73,7 +72,7 @@ startDaemon() {
     # Start the daemon, wait for the socket to appear.  !!!
     # ‘nix-daemon’ should have an option to fork into the background.
     rm -f $NIX_STATE_DIR/daemon-socket/socket
-    nix daemon &
+    ${NIX_DAEMON_COMMAND:-nix daemon} &
     for ((i = 0; i < 30; i++)); do
         if [ -e $NIX_DAEMON_SOCKET_PATH ]; then break; fi
         sleep 1
diff --git a/tests/local.mk b/tests/local.mk
index de095c117..dd9a0ad56 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -6,7 +6,7 @@ nix_tests = \
   gc-auto.sh \
   referrers.sh user-envs.sh logging.sh nix-build.sh misc.sh fixed.sh \
   gc-runtime.sh check-refs.sh filter-source.sh \
-  local-store.sh remote-store.sh export.sh export-graph.sh \
+  local-store.sh remote-store.sh remote-store-old-daemon.sh export.sh export-graph.sh \
   timeout.sh secure-drv-outputs.sh nix-channel.sh \
   multiple-outputs.sh import-derivation.sh fetchurl.sh optimise-store.sh \
   binary-cache.sh \
diff --git a/tests/remote-store-old-daemon.sh b/tests/remote-store-old-daemon.sh
new file mode 100644
index 000000000..ede7ce716
--- /dev/null
+++ b/tests/remote-store-old-daemon.sh
@@ -0,0 +1,7 @@
+# Test that the new Nix can properly talk to an old daemon.
+# If `$OUTER_NIX` isn't set (e.g. when bootsraping), just skip this test
+
+if [[ -n "$OUTER_NIX" ]]; then
+    export NIX_DAEMON_COMMAND=$OUTER_NIX/bin/nix-daemon
+    source remote-store.sh
+fi
diff --git a/tests/remote-store.sh b/tests/remote-store.sh
index f7ae1a2ed..31210ab47 100644
--- a/tests/remote-store.sh
+++ b/tests/remote-store.sh
@@ -23,12 +23,12 @@ startDaemon
 
 storeCleared=1 NIX_REMOTE_=$NIX_REMOTE $SHELL ./user-envs.sh
 
+nix-store --gc --max-freed 1K
+
 nix-store --dump-db > $TEST_ROOT/d1
 NIX_REMOTE= nix-store --dump-db > $TEST_ROOT/d2
 cmp $TEST_ROOT/d1 $TEST_ROOT/d2
 
-nix-store --gc --max-freed 1K
-
 killDaemon
 
 user=$(whoami)