diff --git a/release.nix b/release.nix
index f9ee07e34..fdf3fa946 100644
--- a/release.nix
+++ b/release.nix
@@ -249,6 +249,18 @@ let
           su - alice -c '_NIX_INSTALLER_TEST=1 ./nix-*/install'
           su - alice -c 'nix-store --verify'
           su - alice -c 'PAGER= nix-store -qR ${build.x86_64-linux}'
+
+          # Check whether 'nix upgrade-nix' works.
+          (! [ -L /nix/var/nix/profiles/per-user/alice/profile-2-link ])
+          cat > /tmp/paths.nix <<EOF
+          {
+            x86_64-linux = "${build.x86_64-linux}";
+          }
+          EOF
+          su - alice -c 'nix upgrade-nix -vvv --nix-store-paths-url file:///tmp/paths.nix'
+          [ -L /nix/var/nix/profiles/per-user/alice/profile-2-link ]
+          su - alice -c 'PAGER= nix-store -qR ${build.x86_64-linux}'
+
           mkdir -p $out/nix-support
           touch $out/nix-support/hydra-build-products
           umount /nix
diff --git a/src/nix/upgrade-nix.cc b/src/nix/upgrade-nix.cc
index e23ae7923..4f4d0ebc0 100644
--- a/src/nix/upgrade-nix.cc
+++ b/src/nix/upgrade-nix.cc
@@ -9,6 +9,7 @@ using namespace nix;
 struct CmdUpgradeNix : StoreCommand
 {
     Path profileDir;
+    std::string storePathsUrl = "https://github.com/NixOS/nixpkgs/raw/master/nixos/modules/installer/tools/nix-fallback-paths.nix";
 
     CmdUpgradeNix()
     {
@@ -18,6 +19,12 @@ struct CmdUpgradeNix : StoreCommand
             .labels({"profile-dir"})
             .description("the Nix profile to upgrade")
             .dest(&profileDir);
+
+        mkFlag()
+            .longName("nix-store-paths-url")
+            .labels({"url"})
+            .description("URL of the file that contains the store paths of the latest Nix release")
+            .dest(&storePathsUrl);
     }
 
     std::string name() override
@@ -115,7 +122,7 @@ struct CmdUpgradeNix : StoreCommand
     Path getLatestNix(ref<Store> store)
     {
         // FIXME: use nixos.org?
-        auto req = DownloadRequest("https://github.com/NixOS/nixpkgs/raw/master/nixos/modules/installer/tools/nix-fallback-paths.nix");
+        auto req = DownloadRequest(storePathsUrl);
         auto res = getDownloader()->download(req);
 
         auto state = std::make_unique<EvalState>(Strings(), store);