diff --git a/pyproject.toml b/pyproject.toml
index 0b5c022cd..8e2ef6e98 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -77,11 +77,11 @@ dev = [
 [project.optional-dependencies]
 
 cpu = [
-  'torch==2.6.0',
+  'torch==2.9.1',
 ]
 
 gpu = [
-  "torch==2.6.0; sys_platform == 'linux'",
+  "torch==2.9.1; sys_platform == 'linux'",
   # flash-attn also has a torch dependency.
   "flash-attn",
 ]
@@ -167,7 +167,7 @@ link-mode = "symlink"
 # by future releases of dependencies or sub-dependencies. 
 # See https://docs.astral.sh/uv/reference/settings/#exclude-newer
 # TODO: pytorch does not publish valid release timestamps, so sadly it does not work.
-exclude-newer = "2026-02-27T00:00:00Z"
+exclude-newer = "2026-04-27T00:00:00Z"
 
 # The minimum version of uv required.
 # It is tightly controlled because the format of uv.lock has changed 
@@ -192,12 +192,6 @@ conflicts = [
 ]
 
 
-[[tool.uv.index]]
-name = "pytorch-cu126"
-url = "https://download.pytorch.org/whl/cu126"
-explicit = true
-
-
 [tool.pyrefly]
 project-includes = ["src/"]
 project-excludes = [
@@ -232,25 +226,19 @@ weathergen-readers-extra = { workspace = true }
 
 
 flash-attn = [
-# The build of Cathal O'Brien is not compatible with the libc build on santis.
-# Hardcode the reference to the swiss cluster for the time being.
-# TODO: open issue
-#  { url = "https://github.com/cathalobrien/get-flash-attn/releases/download/v0.1-alpha/flash_attn-2.7.4+cu12torch2.6cxx11abiFALSE-cp312-cp312-linux_aarch64.whl", marker = "sys_platform == 'linux' and platform_machine == 'aarch64'" },
-# This version was rebuilt locally on santis and uploaded.
-  { url = "https://object-store.os-api.cci1.ecmwf.int/weathergenerator-dev/wheels/flash_attn-2.7.3-cp312-cp312-linux_aarch64.whl", marker = "sys_platform == 'linux' and platform_machine == 'aarch64'" },
-  { url = "https://github.com/Dao-AILab/flash-attention/releases/download/v2.7.4.post1/flash_attn-2.7.4.post1+cu12torch2.6cxx11abiTRUE-cp312-cp312-linux_x86_64.whl", marker = "sys_platform == 'linux'  and platform_machine == 'x86_64'" },
+  { url = "https://github.com/Dao-AILab/flash-attention/releases/download/v2.8.3/flash_attn-2.8.3+cu12torch2.9cxx11abiTRUE-cp312-cp312-linux_aarch64.whl", marker = "sys_platform == 'linux' and platform_machine == 'aarch64'" },
+  { url = "https://github.com/cathalobrien/get-flash-attn/releases/download/v0.1-alpha/flash_attn-2.8.3+cu12torch2.9cxx11abiFALSE-cp312-cp312-linux_x86_64.whl", marker = "sys_platform == 'linux'  and platform_machine == 'x86_64'" },
   # There is no official support for flash-attn on macos
 ]
 
-
 torch = [
 # Explicit pin for GPU
-  { url = "https://download.pytorch.org/whl/cu126/torch-2.6.0%2Bcu126-cp312-cp312-linux_aarch64.whl", marker = 'sys_platform == "linux" and platform_machine == "aarch64"', extra="gpu" },
-  { url = "https://download.pytorch.org/whl/cu126/torch-2.6.0%2Bcu126-cp312-cp312-manylinux_2_28_x86_64.whl", marker = 'sys_platform == "linux"  and platform_machine == "x86_64"', extra="gpu" },
+  { url = "https://download-r2.pytorch.org/whl/cu126/torch-2.9.1+cu126-cp312-cp312-manylinux_2_28_aarch64.whl", marker = 'sys_platform == "linux" and platform_machine == "aarch64"', extra="gpu" },
+  { url = "https://download-r2.pytorch.org/whl/cu126/torch-2.9.1+cu126-cp312-cp312-manylinux_2_28_x86_64.whl", marker = 'sys_platform == "linux"  and platform_machine == "x86_64"', extra="gpu" },
 # Explicit pin for CPU.
-  { url = "https://download.pytorch.org/whl/cpu/torch-2.6.0%2Bcpu-cp312-cp312-linux_x86_64.whl",marker = "sys_platform == 'linux' and platform_machine == 'x86_64'",extra = "cpu" },
-  { url = "https://download.pytorch.org/whl/cpu/torch-2.6.0%2Bcpu-cp312-cp312-manylinux_2_28_aarch64.whl",marker = "sys_platform == 'linux' and platform_machine == 'aarch64'",extra = "cpu" },
-  { url = "https://download.pytorch.org/whl/cpu/torch-2.6.0-cp312-none-macosx_11_0_arm64.whl",marker = "sys_platform == 'darwin'", extra="cpu" },
+  { url = "https://download-r2.pytorch.org/whl/cpu/torch-2.9.1+cpu-cp312-cp312-manylinux_2_28_aarch64.whl",marker = "sys_platform == 'linux' and platform_machine == 'aarch64'",extra = "cpu" },
+  { url = "https://download-r2.pytorch.org/whl/cpu/torch-2.9.1+cpu-cp312-cp312-manylinux_2_28_x86_64.whl",marker = "sys_platform == 'linux' and platform_machine == 'x86_64'",extra = "cpu" },
+
   # No acceleration for now.
   # TODO: explore pytorch + metal backend
   { index = "pytorch-cpu", marker = "sys_platform == 'darwin'", extra="gpu"},