diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 19629872d433996e4a6c7e33e58797c85295a44e..0cb27b199907e532ee4ec542608e706c702322c9 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -14,6 +14,7 @@ cache:
   paths:
     - .cache/pip
     - venv/
+    - .cache/apt
 
 stages:
   - build
@@ -28,6 +29,10 @@ before_script:
 dist:
   stage: build
   script:
+    - mkdir -p .cache/apt
+    - apt-get update -yqq
+    - apt-get install -y gfortran libopenblas-dev liblapack-dev
+    - apt-get -o dir::cache::archives=".cache/apt" install -y -qq gfortran liblapack-dev libgmp-dev
     - python setup.py bdist_wheel
     # an alternative approach is to install and run:
     - pip install dist/*
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 4b8f505150295f872a56c491c035f967ad0dc84d..11cc3049ed15c86b247275f4d2a96fd5590b7070 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,15 +1,16 @@
+default_language_version:
+    python: python3
 repos:
 -   repo: https://github.com/ambv/black
-    rev: stable
+    rev: 21.6b0
     hooks:
     - id: black
-      language_version: python3.6
 -   repo: https://gitlab.com/pycqa/flake8
-    rev: 3.8.3
+    rev: 3.9.2
     hooks:
     - id: flake8
 -   repo: https://github.com/pre-commit/pre-commit-hooks 
-    rev: v3.1.0
+    rev: v4.0.1
     hooks:
     - id: check-json
     - id: pretty-format-json
@@ -21,6 +22,6 @@ repos:
     - id: detect-private-key
     - id: end-of-file-fixer
 -   repo: https://github.com/asottile/blacken-docs
-    rev: v1.7.0
+    rev: v1.10.0
     hooks:
     - id: blacken-docs
diff --git a/LICENSE.rst b/LICENSE.rst
index fbeca6d09567375f1bd12a6036c7a2b140f5eb2e..5f8b4edff863e691e6c40ffb30facb001bb4d7ea 100644
--- a/LICENSE.rst
+++ b/LICENSE.rst
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2020, Daniel Böckenhoff
+Copyright (c) 2021, Daniel Böckenhoff
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/docs/cookiecutter_input.json b/docs/cookiecutter_input.json
index 5e5cf5361dab19da09a11ddb4ed28d8481e43b8d..61341d1d1108bb9d87c98ef3dbb102b81a880f63 100644
--- a/docs/cookiecutter_input.json
+++ b/docs/cookiecutter_input.json
@@ -9,7 +9,7 @@
     "email": "dboe@ipp.mpg.de",
     "keywords": "tensors, tensor-fields, graphs, mesh, numpy, math",
     "package_name": "tfields",
-    "package_version": "0.3.2",
+    "package_version": "0.3.7",
     "pypi_username": "dboe",
     "remote_namespace": "dboe",
     "remote_provider": "gitlab.mpcdf.mpg.de",
diff --git a/setup.cfg b/setup.cfg
index 9bf0792dbd02ae04d86c29111e9e414a1797568b..ebe47bbe20e5884077ecf7b03b8b28f2d5964b93 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 0.3.2
+current_version = 0.3.7
 tag = True
 commit = True
 message = release-v{new_version}
diff --git a/setup.py b/setup.py
index 76d623ec3cd30f0773194b442702d387ef4b3515..6003a891bd18b55d4826813862b484d9e2b51e71 100644
--- a/setup.py
+++ b/setup.py
@@ -1,3 +1,3 @@
 from setuptools import setup
 
-setup(version="0.3.2")
+setup(version="0.3.7")
diff --git a/tfields/__init__.py b/tfields/__init__.py
index 38c9a96c0983080d77cb9405a7dbbfeb3377ba54..faabd6e16b9abd925106ab5620aea2d341001535 100644
--- a/tfields/__init__.py
+++ b/tfields/__init__.py
@@ -2,4 +2,4 @@
 
 __author__ = """Daniel Böckenhoff"""
 __email__ = "dboe@ipp.mpg.de"
-__version__ = "0.3.2"
+__version__ = "0.3.7"