diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0a2d45fe9c8d83de81d5859fd4836d3746170d73..f7ed796ccf4d970264ea8b0a2c6ab7461fd5ebc5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,7 +3,13 @@
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## v1.3.0 - 2021-22-05
+## v1.3.1 - 2021-09-25
+
+### `Fixed`
+
+* Fix bug in conda environment for cooltools (#109)
+
+## v1.3.0 - 2021-05-22
 
 * Change the `/tmp/` folder to `./tmp/` folder so that all tmp files are now in the work directory (#24)
 * Add `--hicpro_maps` options to generate the raw and normalized HiC-Pro maps. The default is now to use cooler
diff --git a/environment.yml b/environment.yml
index 9d357598b764a0dbf9adbeccd3fe6767828fa844..e3cd7576274730a4a3e7c76e8431993726bcc47d 100644
--- a/environment.yml
+++ b/environment.yml
@@ -16,6 +16,7 @@ dependencies:
   - bioconda::pysam=0.15.4
   - conda-forge::pymdown-extensions=7.1
   - bioconda::cooler=0.8.6
+  - bioconda::cooltools=0.4.0
   - bioconda::bowtie2=2.3.5
   - bioconda::samtools=1.9
   - bioconda::multiqc=1.8
@@ -27,5 +28,4 @@ dependencies:
   - bioconda::ucsc-bedgraphtobigwig=357
   - conda-forge::cython=0.29.19
   - pip:
-    - cooltools==0.4.0
     - fanc==0.8.30
\ No newline at end of file
diff --git a/nextflow.config b/nextflow.config
index 7296cc2af450343641614486f3cc232b25c71243..2f8fd5776c8514fbf5dcf438b3121961a7757547 100644
--- a/nextflow.config
+++ b/nextflow.config
@@ -225,7 +225,7 @@ manifest {
   description = 'Analysis of Chromosome Conformation Capture data (Hi-C)'
   mainScript = 'main.nf'
   nextflowVersion = '>=20.04.0'
-  version = '1.3.0'
+  version = '1.3.1'
 }
 
 // Function to ensure that resource requirements don't go beyond