diff --git a/.swift-version b/.swift-version
index 55167b9ac..01e98ba4f 100644
--- a/.swift-version
+++ b/.swift-version
@@ -1 +1 @@
-wasm-DEVELOPMENT-SNAPSHOT-2020-06-12-a
+wasm-5.3-SNAPSHOT-2020-07-27-a
diff --git a/Package.resolved b/Package.resolved
index b16a32101..04662b69f 100644
--- a/Package.resolved
+++ b/Package.resolved
@@ -14,8 +14,8 @@
         "package": "OpenCombine",
         "repositoryURL": "https://github.com/MaxDesiatov/OpenCombine.git",
         "state": {
-          "branch": "observable-object",
-          "revision": "3c3a181acad7ab44a64d7c41140eb843222bb2aa",
+          "branch": "observable-object-5.3",
+          "revision": "979d83e8725a504567827b89a5656bf4fd36d0c6",
           "version": null
         }
       },
@@ -23,8 +23,8 @@
         "package": "Runtime",
         "repositoryURL": "https://github.com/MaxDesiatov/Runtime.git",
         "state": {
-          "branch": "wasi-build",
-          "revision": "a9309b4822d6dd0e4a8e92351ee9e3d210e19b4e",
+          "branch": "wasi-build-5.3",
+          "revision": "a617ead8a125a97e69d6100e4d27922006e82e0a",
           "version": null
         }
       }
diff --git a/Package.swift b/Package.swift
index a2e9ca67a..dd1e07cae 100644
--- a/Package.swift
+++ b/Package.swift
@@ -38,8 +38,11 @@ let package = Package(
     // Dependencies declare other packages that this package depends on.
     // .package(url: /* package url */, from: "1.0.0"),
     .package(url: "https://github.com/kateinoigakukun/JavaScriptKit.git", .revision("c90e82f")),
-    .package(url: "https://github.com/MaxDesiatov/Runtime.git", .branch("wasi-build")),
-    .package(url: "https://github.com/MaxDesiatov/OpenCombine.git", .branch("observable-object")),
+    .package(url: "https://github.com/MaxDesiatov/Runtime.git", .branch("wasi-build-5.3")),
+    .package(
+      url: "https://github.com/MaxDesiatov/OpenCombine.git",
+      .branch("observable-object-5.3")
+    ),
   ],
   targets: [
     // Targets are the basic building blocks of a package. A target can define