diff --git a/conda/environments/cgat-apps.yml b/conda/environments/cgat-apps.yml
index 2502db80d..d7c3b01be 100644
--- a/conda/environments/cgat-apps.yml
+++ b/conda/environments/cgat-apps.yml
@@ -23,7 +23,7 @@ dependencies:
 - pep8
 - pybedtools
 - pybigwig
-- pysam>=0.15.4
+- pysam=0.15.2
 - python-lzo
 - pyyaml
 - quicksect