diff --git a/scripts/ci/js-sdk-to-release.sh b/scripts/ci/js-sdk-to-release.sh
new file mode 100755
index 0000000000..a03165bd82
--- /dev/null
+++ b/scripts/ci/js-sdk-to-release.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+# This changes the js-sdk into 'release mode', that is:
+# * The entry point for the library is the babel-compiled lib/index.js rather than src/index.ts
+# * There's a 'typings' entry referencing the types output by tsc
+# We do this so we can test that each PR still builds / type checks correctly when built
+# against the released js-sdk, because if you do things like `import { User } from 'matrix-js-sdk';`
+# rather than `import { User } from 'matrix-js-sdk/src/models/user';` it will work fine with the
+# js-sdk in development mode but then break at release time.
+# We can't use the last release of the js-sdk though: it might not be up to date enough.
+
+cd node_modules/matrix-js-sdk
+for i in main typings
+do
+    lib_value=$(jq -r ".matrix_lib_$i" package.json)
+    if [ "$lib_value" != "null" ]; then
+        jq ".$i = .matrix_lib_$i" package.json > package.json.new && mv package.json.new package.json
+    fi
+done
+yarn run build:compile
+yarn run build:types
diff --git a/src/resizer/resizer.ts b/src/resizer/resizer.ts
index 19af425b8b..0db13e1af5 100644
--- a/src/resizer/resizer.ts
+++ b/src/resizer/resizer.ts
@@ -84,7 +84,7 @@ export default class Resizer<C extends IConfig = IConfig> {
     }
 
     public detach() {
-        const attachment = this?.config?.handler.parentElement ?? this.container;
+        const attachment = this?.config?.handler?.parentElement ?? this.container;
         attachment.removeEventListener("mousedown", this.onMouseDown, false);
         window.removeEventListener("resize", this.onResize);
     }
diff --git a/src/sentry.ts b/src/sentry.ts
index 59152f66f2..206ff9811b 100644
--- a/src/sentry.ts
+++ b/src/sentry.ts
@@ -19,7 +19,7 @@ import PlatformPeg from "./PlatformPeg";
 import SdkConfig from "./SdkConfig";
 import { MatrixClientPeg } from "./MatrixClientPeg";
 import SettingsStore from "./settings/SettingsStore";
-import { MatrixClient } from "matrix-js-sdk";
+import { MatrixClient } from "matrix-js-sdk/src/client";
 
 /* eslint-disable camelcase */