diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index 93d592f8..d8c19316 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -14,7 +14,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [ 3.6, 3.7, 3.8 ]
+        python-version: [ 3.7, 3.8 ]
         rasterio-version: [ 1.1.4, "latest" ]
         experimental: [ false ]
     runs-on: ubuntu-latest
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 96d6b6a3..c585986d 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -2,6 +2,18 @@
 Changelog
 #########
 
+-----------------
+0.40 - 2021-06-24
+-----------------
+
+* core
+
+  * fix overviews creation in sinlge GTiff output (#325)
+
+* packaging
+
+  * drop Python 3.6 support
+
 
 -----------------
 0.39 - 2021-06-08
diff --git a/mapchete/__init__.py b/mapchete/__init__.py
index fa234199..eaca058b 100644
--- a/mapchete/__init__.py
+++ b/mapchete/__init__.py
@@ -7,7 +7,7 @@
 
 
 __all__ = ["open", "count_tiles", "Mapchete", "MapcheteProcess", "Timer"]
-__version__ = "0.39"
+__version__ = "0.40"
 
 
 logger = logging.getLogger(__name__)
diff --git a/requirements.txt b/requirements.txt
index d4f7ef27..945401b5 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,7 +9,7 @@ click-plugins>=1.1.1
 click-spinner>=0.1.10
 fiona>=1.8.13.post1
 Flask>=1.1.2
-fsspec[s3]>=0.8.4
+fsspec[s3]==0.8.4
 geobuf>=1.1.1
 importlib-metadata>=1.6.0
 importlib-resources>=1.5.0
@@ -19,7 +19,7 @@ numpy>=1.16
 oyaml>=0.9
 retry>=0.9.2
 rasterio>=1.0.28
-s3fs>=0.5.1
+s3fs==0.5.2
 Shapely>=1.7.1
 tilematrix>=0.20
 tqdm>=4.46.0
diff --git a/setup.py b/setup.py
index c376a200..4d6288bf 100644
--- a/setup.py
+++ b/setup.py
@@ -113,7 +113,6 @@
         "Intended Audience :: Developers",
         "Topic :: Scientific/Engineering :: GIS",
         "License :: OSI Approved :: MIT License",
-        "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
     ],