diff --git a/.azure-pipelines/ci-conda-env.txt b/.azure-pipelines/ci-conda-env.txt
index d9c93bc90..23081b8ff 100644
--- a/.azure-pipelines/ci-conda-env.txt
+++ b/.azure-pipelines/ci-conda-env.txt
@@ -1,10 +1,10 @@
 conda-forge::boost
 conda-forge::boost-cpp
 conda-forge::bzip2
-conda-forge::c-compiler<1.5
+conda-forge::c-compiler
 conda-forge::cctbx-base
 conda-forge::conda
-conda-forge::cxx-compiler<1.5
+conda-forge::cxx-compiler
 conda-forge::python-dateutil
 conda-forge::dials-data
 conda-forge::docutils
@@ -16,7 +16,7 @@ conda-forge::hdf5
 conda-forge::matplotlib-base
 conda-forge::mrcfile
 conda-forge::natsort
-conda-forge::numpy
+conda-forge::numpy<2
 conda-forge::nxmx
 conda-forge::orderedset
 conda-forge::pillow>=5.4.1
diff --git a/newsfragments/750.misc b/newsfragments/750.misc
new file mode 100644
index 000000000..af2ac0bf2
--- /dev/null
+++ b/newsfragments/750.misc
@@ -0,0 +1 @@
+Fix CI by pinning numpy 2.0.