diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e1d44da9..f953c6c0 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -34,18 +34,18 @@ If you're building Fractal with Flatpak (via GNOME Builder or the command line),
 manually add the necessary remotes and install the required freedesktop.org extensions:
 
 ```sh
-# Add Flathub and the gnome-nightly repo
-flatpak remote-add --user --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
+# Add Flathub beta and the gnome-nightly repo
+flatpak remote-add --user --if-not-exists flathub-beta https://flathub.org/beta-repo/flathub-beta.flatpakrepo
 flatpak remote-add --user --if-not-exists gnome-nightly https://nightly.gnome.org/gnome-nightly.flatpakrepo
 
 # Install the gnome-nightly Sdk and Platform runtime
 flatpak install --user gnome-nightly org.gnome.Sdk//master org.gnome.Platform//master
 
-# Install the required rust-stable extension from Flathub
-flatpak install --user flathub org.freedesktop.Sdk.Extension.rust-stable//23.08
+# Install the required rust-stable extension from Flathub beta
+flatpak install --user flathub-beta org.freedesktop.Sdk.Extension.rust-stable//24.08beta
 
-# Install the required llvm extension from Flathub
-flatpak install --user flathub org.freedesktop.Sdk.Extension.llvm16//23.08
+# Install the required llvm extension from Flathub beta
+flatpak install --user flathub-beta org.freedesktop.Sdk.Extension.llvm18//24.08beta
 ```
 
 If you are building the flatpak manually you will also need flatpak-builder on your system, or the
diff --git a/build-aux/org.gnome.Fractal.Devel.json b/build-aux/org.gnome.Fractal.Devel.json
index 80825b9a..fca1a937 100644
--- a/build-aux/org.gnome.Fractal.Devel.json
+++ b/build-aux/org.gnome.Fractal.Devel.json
@@ -5,7 +5,7 @@
     "sdk": "org.gnome.Sdk",
     "sdk-extensions": [
         "org.freedesktop.Sdk.Extension.rust-stable",
-        "org.freedesktop.Sdk.Extension.llvm16"
+        "org.freedesktop.Sdk.Extension.llvm18"
     ],
     "command": "fractal",
     "finish-args": [
@@ -21,8 +21,8 @@
         "--env=NO_POINTER_VIEWPORT=1"
     ],
     "build-options": {
-        "append-ld-library-path": "/usr/lib/sdk/llvm16/lib",
-        "append-path": "/usr/lib/sdk/llvm16/bin:/usr/lib/sdk/rust-stable/bin",
+        "append-ld-library-path": "/usr/lib/sdk/llvm18/lib",
+        "append-path": "/usr/lib/sdk/llvm18/bin:/usr/lib/sdk/rust-stable/bin",
         "env": {
             "CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER": "clang",
             "CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUSTFLAGS": "-C link-arg=-fuse-ld=/usr/lib/sdk/rust-stable/bin/mold --cfg=ruma_identifiers_storage=\"Arc\"",