diff --git a/cuda_core/pixi.lock b/cuda_core/pixi.lock
index 4b7d2809cf..757209b36b 100644
--- a/cuda_core/pixi.lock
+++ b/cuda_core/pixi.lock
@@ -11,6 +11,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/linux-64/alsa-lib-1.2.15.3-hb03c661_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/aom-3.9.1-hac33072_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/attr-2.5.2-h39aace5_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/binutils_impl_linux-64-2.45.1-default_hfdba357_101.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/bzip2-1.0.8-hda65f42_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-hbd8a1cb_0.conda
@@ -225,6 +226,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/aom-3.9.1-hcccb83c_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/arm-variant-1.2.0-sbsa.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/attr-2.5.1-h4e544f5_1.tar.bz2
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/binutils_impl_linux-aarch64-2.45.1-default_h5f4c503_101.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/bzip2-1.0.8-h4777abc_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-hbd8a1cb_0.conda
@@ -426,6 +428,7 @@ environments:
       win-64:
       - conda: https://conda.anaconda.org/conda-forge/win-64/_openmp_mutex-4.5-20_gnu.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/aom-3.9.1-he0c23c2_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/binutils_impl_win-64-2.45.1-default_ha84baeb_101.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/bzip2-1.0.8-h0ad9c76_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-h4c7d964_0.conda
@@ -583,6 +586,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/linux-64/alsa-lib-1.2.15.3-hb03c661_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/aom-3.9.1-hac33072_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/attr-2.5.2-h39aace5_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/binutils_impl_linux-64-2.45.1-default_hfdba357_101.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/bzip2-1.0.8-hda65f42_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-hbd8a1cb_0.conda
@@ -793,6 +797,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/aom-3.9.1-hcccb83c_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/arm-variant-1.2.0-sbsa.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/attr-2.5.1-h4e544f5_1.tar.bz2
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/binutils_impl_linux-aarch64-2.45.1-default_h5f4c503_101.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/bzip2-1.0.8-h4777abc_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-hbd8a1cb_0.conda
@@ -990,6 +995,7 @@ environments:
       win-64:
       - conda: https://conda.anaconda.org/conda-forge/win-64/_openmp_mutex-4.5-20_gnu.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/aom-3.9.1-he0c23c2_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/binutils_impl_win-64-2.45.1-default_ha84baeb_101.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/bzip2-1.0.8-h0ad9c76_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-h4c7d964_0.conda
@@ -1141,6 +1147,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/linux-64/alsa-lib-1.2.15.3-hb03c661_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/aom-3.9.1-hac33072_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/attr-2.5.2-h39aace5_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/binutils_impl_linux-64-2.45.1-default_hfdba357_101.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/bzip2-1.0.8-hda65f42_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-hbd8a1cb_0.conda
@@ -1351,6 +1358,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/aom-3.9.1-hcccb83c_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/arm-variant-1.2.0-sbsa.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/attr-2.5.1-h4e544f5_1.tar.bz2
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/binutils_impl_linux-aarch64-2.45.1-default_h5f4c503_101.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/bzip2-1.0.8-h4777abc_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-hbd8a1cb_0.conda
@@ -1548,6 +1556,7 @@ environments:
       win-64:
       - conda: https://conda.anaconda.org/conda-forge/win-64/_openmp_mutex-4.5-20_gnu.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/aom-3.9.1-he0c23c2_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/binutils_impl_win-64-2.45.1-default_ha84baeb_101.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/bzip2-1.0.8-h0ad9c76_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-h4c7d964_0.conda
@@ -1707,6 +1716,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/noarch/attrs-26.1.0-pyhcf101f3_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/autodocsumm-0.2.15-pyhd8ed1ab_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/babel-2.18.0-pyhcf101f3_1.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/backports.zstd-1.3.0-py314h680f03e_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/beautifulsoup4-4.14.3-pyha770c72_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/brotli-python-1.2.0-py314h3de4e8d_1.conda
@@ -1890,6 +1900,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/noarch/attrs-26.1.0-pyhcf101f3_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/autodocsumm-0.2.15-pyhd8ed1ab_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/babel-2.18.0-pyhcf101f3_1.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/backports.zstd-1.3.0-py314h680f03e_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/beautifulsoup4-4.14.3-pyha770c72_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/brotli-python-1.2.0-py314h352cb57_1.conda
@@ -2071,6 +2082,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/noarch/attrs-26.1.0-pyhcf101f3_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/autodocsumm-0.2.15-pyhd8ed1ab_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/babel-2.18.0-pyhcf101f3_1.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/backports.zstd-1.3.0-py314h680f03e_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/beautifulsoup4-4.14.3-pyha770c72_0.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/brotli-python-1.2.0-py314he701e3d_1.conda
@@ -2243,6 +2255,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/linux-64/alsa-lib-1.2.15.3-hb03c661_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/aom-3.9.1-hac33072_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/attr-2.5.2-h39aace5_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/binutils_impl_linux-64-2.45.1-default_hfdba357_101.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/bzip2-1.0.8-hda65f42_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-hbd8a1cb_0.conda
@@ -2473,6 +2486,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/aom-3.9.1-hcccb83c_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/arm-variant-1.2.0-sbsa.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/attr-2.5.1-h4e544f5_1.tar.bz2
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/binutils_impl_linux-aarch64-2.45.1-default_h5f4c503_101.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-aarch64/bzip2-1.0.8-h4777abc_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-hbd8a1cb_0.conda
@@ -2692,6 +2706,7 @@ environments:
       - conda: ../cuda_pathfinder
       win-64:
       - conda: https://conda.anaconda.org/conda-forge/win-64/aom-3.9.1-he0c23c2_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/bzip2-1.0.8-h0ad9c76_9.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.2.25-h4c7d964_0.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/cairo-1.18.4-h477c42c_1.conda
@@ -3043,6 +3058,17 @@ packages:
   - pkg:pypi/babel?source=compressed-mapping
   size: 7684321
   timestamp: 1772555330347
+- conda: https://conda.anaconda.org/conda-forge/noarch/backports.strenum-1.3.1-haf276df_2.conda
+  noarch: python
+  sha256: b3d3ae7769fd5a454417ce791b72cfeab77c85cb532e3d0c41d2bf70b07b5416
+  md5: 1e58854a1a742a8d94d862b626cf4057
+  depends:
+  - python >=3.12
+  license: PSF-2.0
+  license_family: PSF
+  purls: []
+  size: 9849
+  timestamp: 1736184616857
 - conda: https://conda.anaconda.org/conda-forge/noarch/backports.zstd-1.3.0-py314h680f03e_0.conda
   noarch: generic
   sha256: c31ab719d256bc6f89926131e88ecd0f0c5d003fe8481852c6424f4ec6c7eb29
@@ -3670,6 +3696,7 @@ packages:
   - numpy
   - cuda-bindings
   - cuda-pathfinder
+  - backports.strenum
   - vc >=14.3,<15
   - vc14_runtime >=14.44.35208
   - ucrt >=10.0.20348.0
@@ -3693,6 +3720,7 @@ packages:
   - numpy
   - cuda-bindings
   - cuda-pathfinder
+  - backports.strenum
   - vc >=14.3,<15
   - vc14_runtime >=14.44.35208
   - ucrt >=10.0.20348.0
@@ -3715,6 +3743,7 @@ packages:
   - numpy
   - cuda-bindings
   - cuda-pathfinder
+  - backports.strenum
   - libgcc >=15
   - libgcc >=15
   - libstdcxx >=15
@@ -3737,6 +3766,7 @@ packages:
   - numpy
   - cuda-bindings
   - cuda-pathfinder
+  - backports.strenum
   - libgcc >=15
   - libgcc >=15
   - libstdcxx >=15
@@ -3759,6 +3789,7 @@ packages:
   - numpy
   - cuda-bindings
   - cuda-pathfinder
+  - backports.strenum
   - libgcc >=15
   - libgcc >=15
   - libstdcxx >=15
@@ -3781,6 +3812,7 @@ packages:
   - numpy
   - cuda-bindings
   - cuda-pathfinder
+  - backports.strenum
   - libgcc >=15
   - libgcc >=15
   - libstdcxx >=15
diff --git a/cuda_core/pixi.toml b/cuda_core/pixi.toml
index df5111497f..5e62655717 100644
--- a/cuda_core/pixi.toml
+++ b/cuda_core/pixi.toml
@@ -185,8 +185,10 @@ cuda-version = "*"
 numpy = "*"
 cuda-bindings = "*"
 cuda-pathfinder = "*"
-
-[package.target.'python_version < "3.11"'.run-dependencies]
+# Conda-forge ships per-Python variants of backports.strenum (real impl on
+# <3.11, no-op stub on >=3.12); pixi-build doesn't accept PEP 508-style
+# `python_version` selectors in [package.target.<X>], so list it
+# unconditionally and let the solver pick the right variant.
 "backports.strenum" = "*"
 
 [target.linux.tasks.build-cython-tests]