diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 56f7167..91141a8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,7 +6,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.8, 3.9]
+        python-version: [3.7, 3.8, 3.9]
         os: [ubuntu-20.04]
     runs-on: ${{ matrix.os }}
     steps:
diff --git a/poetry.lock b/poetry.lock
index 9e1c5e8..946d4b4 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -191,6 +191,7 @@ optional = false
 python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,>=2.7"
 
 [package.dependencies]
+importlib-metadata = {version = "*", markers = "python_version < \"3.8\""}
 mccabe = ">=0.6.0,<0.7.0"
 pycodestyle = ">=2.6.0a1,<2.7.0"
 pyflakes = ">=2.2.0,<2.3.0"
@@ -345,6 +346,21 @@ category = "main"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
+[[package]]
+name = "importlib-metadata"
+version = "2.1.1"
+description = "Read metadata from Python packages"
+category = "dev"
+optional = false
+python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
+
+[package.dependencies]
+zipp = ">=0.5"
+
+[package.extras]
+docs = ["sphinx", "rst.linker"]
+testing = ["packaging", "pep517", "unittest2", "importlib-resources (>=1.3)"]
+
 [[package]]
 name = "iniconfig"
 version = "1.1.1"
@@ -455,6 +471,9 @@ category = "dev"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
+[package.dependencies]
+importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
+
 [package.extras]
 dev = ["pre-commit", "tox"]
 
@@ -524,6 +543,7 @@ python-versions = ">=3.6"
 atomicwrites = {version = ">=1.0", markers = "sys_platform == \"win32\""}
 attrs = ">=19.2.0"
 colorama = {version = "*", markers = "sys_platform == \"win32\""}
+importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
 iniconfig = "*"
 packaging = "*"
 pluggy = ">=0.12,<1.0.0a1"
@@ -574,7 +594,7 @@ six = ">=1.5"
 
 [[package]]
 name = "pytz"
-version = "2020.4"
+version = "2020.5"
 description = "World timezone definitions, modern and historical"
 category = "main"
 optional = false
@@ -687,6 +707,7 @@ optional = false
 python-versions = ">=3.6"
 
 [package.dependencies]
+importlib-metadata = {version = ">=1.7.0", markers = "python_version < \"3.8\""}
 pbr = ">=2.0.0,<2.1.0 || >2.1.0"
 
 [[package]]
@@ -740,6 +761,7 @@ python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
 [package.dependencies]
 colorama = {version = ">=0.4.1", markers = "platform_system == \"Windows\""}
 filelock = ">=3.0.0"
+importlib-metadata = {version = ">=0.12,<3", markers = "python_version < \"3.8\""}
 packaging = ">=14"
 pluggy = ">=0.12.0"
 py = ">=1.4.17"
@@ -753,7 +775,7 @@ testing = ["flaky (>=3.4.0)", "freezegun (>=0.3.11)", "pathlib2 (>=2.3.3)", "psu
 
 [[package]]
 name = "typed-ast"
-version = "1.4.1"
+version = "1.4.2"
 description = "a fork of Python 2 and 3 ast modules with type comment support"
 category = "dev"
 optional = false
@@ -803,6 +825,7 @@ python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,>=2.7"
 appdirs = ">=1.4.3,<2"
 distlib = ">=0.3.1,<1"
 filelock = ">=3.0.0,<4"
+importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
 six = ">=1.9.0,<2"
 
 [package.extras]
@@ -822,10 +845,22 @@ lxml = "*"
 python-dateutil = "*"
 requests = "*"
 
+[[package]]
+name = "zipp"
+version = "3.4.0"
+description = "Backport of pathlib-compatible object wrapper for zip files"
+category = "dev"
+optional = false
+python-versions = ">=3.6"
+
+[package.extras]
+docs = ["sphinx", "jaraco.packaging (>=3.2)", "rst.linker (>=1.9)"]
+testing = ["pytest (>=3.5,!=3.7.3)", "pytest-checkdocs (>=1.2.3)", "pytest-flake8", "pytest-cov", "jaraco.test (>=3.2.0)", "jaraco.itertools", "func-timeout", "pytest-black (>=0.3.7)", "pytest-mypy"]
+
 [metadata]
 lock-version = "1.1"
-python-versions = "^3.8"
-content-hash = "b63aefb7e8671e120ee9802d249d2075c78628af272bc8b17155bd994f8a5501"
+python-versions = "^3.7"
+content-hash = "df2ebfe4963aebcf6cd022005f0c8bcadcae226e336d7b5c83dbbe6acd739463"
 
 [metadata.files]
 appdirs = [
@@ -861,7 +896,6 @@ click = [
 ]
 colorama = [
     {file = "colorama-0.4.4-py2.py3-none-any.whl", hash = "sha256:9f47eda37229f68eee03b24b9748937c7dc3868f906e8ba69fbcbdd3bc5dc3e2"},
-    {file = "colorama-0.4.4.tar.gz", hash = "sha256:5941b2b48a20143d2267e95b1c2a7603ce057ee39fd88e7329b0c292aa16869b"},
 ]
 coverage = [
     {file = "coverage-5.3.1-cp27-cp27m-macosx_10_9_x86_64.whl", hash = "sha256:fabeeb121735d47d8eab8671b6b031ce08514c86b7ad8f7d5490a7b6dcd6267d"},
@@ -992,8 +1026,11 @@ idna = [
     {file = "idna-2.10-py2.py3-none-any.whl", hash = "sha256:b97d804b1e9b523befed77c48dacec60e6dcb0b5391d57af6a65a312a90648c0"},
     {file = "idna-2.10.tar.gz", hash = "sha256:b307872f855b18632ce0c21c5e45be78c0ea7ae4c15c828c20788b26921eb3f6"},
 ]
+importlib-metadata = [
+    {file = "importlib_metadata-2.1.1-py2.py3-none-any.whl", hash = "sha256:c2d6341ff566f609e89a2acb2db190e5e1d23d5409d6cc8d2fe34d72443876d4"},
+    {file = "importlib_metadata-2.1.1.tar.gz", hash = "sha256:b8de9eff2b35fb037368f28a7df1df4e6436f578fa74423505b6c6a778d5b5dd"},
+]
 iniconfig = [
-    {file = "iniconfig-1.1.1-py2.py3-none-any.whl", hash = "sha256:011e24c64b7f47f6ebd835bb12a743f2fbe9a26d4cecaa7f53bc4f35ee9da8b3"},
     {file = "iniconfig-1.1.1.tar.gz", hash = "sha256:bc3af051d7d14b2ee5ef9969666def0cd1a000e121eaea580d4a313df4b37f32"},
 ]
 isort = [
@@ -1122,8 +1159,8 @@ python-dateutil = [
     {file = "python_dateutil-2.8.1-py2.py3-none-any.whl", hash = "sha256:75bb3f31ea686f1197762692a9ee6a7550b59fc6ca3a1f4b5d7e32fb98e2da2a"},
 ]
 pytz = [
-    {file = "pytz-2020.4-py2.py3-none-any.whl", hash = "sha256:5c55e189b682d420be27c6995ba6edce0c0a77dd67bfbe2ae6607134d5851ffd"},
-    {file = "pytz-2020.4.tar.gz", hash = "sha256:3e6b7dd2d1e0a59084bcee14a17af60c5c562cdc16d828e8eba2e683d3a7e268"},
+    {file = "pytz-2020.5-py2.py3-none-any.whl", hash = "sha256:16962c5fb8db4a8f63a26646d8886e9d769b6c511543557bc84e9569fb9a9cb4"},
+    {file = "pytz-2020.5.tar.gz", hash = "sha256:180befebb1927b16f6b57101720075a984c019ac16b1b7575673bea42c6c3da5"},
 ]
 pyyaml = [
     {file = "PyYAML-5.3.1-cp27-cp27m-win32.whl", hash = "sha256:74809a57b329d6cc0fdccee6318f44b9b8649961fa73144a98735b0aaf029f1f"},
@@ -1136,8 +1173,6 @@ pyyaml = [
     {file = "PyYAML-5.3.1-cp37-cp37m-win_amd64.whl", hash = "sha256:73f099454b799e05e5ab51423c7bcf361c58d3206fa7b0d555426b1f4d9a3eaf"},
     {file = "PyYAML-5.3.1-cp38-cp38-win32.whl", hash = "sha256:06a0d7ba600ce0b2d2fe2e78453a470b5a6e000a985dd4a4e54e436cc36b0e97"},
     {file = "PyYAML-5.3.1-cp38-cp38-win_amd64.whl", hash = "sha256:95f71d2af0ff4227885f7a6605c37fd53d3a106fcab511b8860ecca9fcf400ee"},
-    {file = "PyYAML-5.3.1-cp39-cp39-win32.whl", hash = "sha256:ad9c67312c84def58f3c04504727ca879cb0013b2517c85a9a253f0cb6380c0a"},
-    {file = "PyYAML-5.3.1-cp39-cp39-win_amd64.whl", hash = "sha256:6034f55dab5fea9e53f436aa68fa3ace2634918e8b5994d82f3621c04ff5ed2e"},
     {file = "PyYAML-5.3.1.tar.gz", hash = "sha256:b8eac752c5e14d3eca0e6dd9199cd627518cb5ec06add0de9d32baeee6fe645d"},
 ]
 regex = [
@@ -1234,36 +1269,36 @@ tox = [
     {file = "tox-3.20.1.tar.gz", hash = "sha256:4321052bfe28f9d85082341ca8e233e3ea901fdd14dab8a5d3fbd810269fbaf6"},
 ]
 typed-ast = [
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+    {file = "typed_ast-1.4.2-cp39-cp39-manylinux1_x86_64.whl", hash = "sha256:d746a437cdbca200622385305aedd9aef68e8a645e385cc483bdc5e488f07166"},
+    {file = "typed_ast-1.4.2-cp39-cp39-manylinux2014_aarch64.whl", hash = "sha256:14bf1522cdee369e8f5581238edac09150c765ec1cb33615855889cf33dcb92d"},
+    {file = "typed_ast-1.4.2-cp39-cp39-win32.whl", hash = "sha256:cc7b98bf58167b7f2db91a4327da24fb93368838eb84a44c472283778fc2446b"},
+    {file = "typed_ast-1.4.2-cp39-cp39-win_amd64.whl", hash = "sha256:7147e2a76c75f0f64c4319886e7639e490fee87c9d25cb1d4faef1d8cf83a440"},
+    {file = "typed_ast-1.4.2.tar.gz", hash = "sha256:9fc0b3cb5d1720e7141d103cf4819aea239f7d136acf9ee4a69b047b7986175a"},
 ]
 typing-extensions = [
     {file = "typing_extensions-3.7.4.3-py2-none-any.whl", hash = "sha256:dafc7639cde7f1b6e1acc0f457842a83e722ccca8eef5270af2d74792619a89f"},
@@ -1285,3 +1320,7 @@ virtualenv = [
 webdavclient3 = [
     {file = "webdavclient3-3.14.5.tar.gz", hash = "sha256:6072f9a583059f8ff313f8544d415b4191fc89bdf6230259b0527b706ab1837b"},
 ]
+zipp = [
+    {file = "zipp-3.4.0-py3-none-any.whl", hash = "sha256:102c24ef8f171fd729d46599845e95c7ab894a4cf45f5de11a44cc7444fb1108"},
+    {file = "zipp-3.4.0.tar.gz", hash = "sha256:ed5eee1974372595f9e416cc7bbeeb12335201d8081ca8a0743c954d4446e5cb"},
+]
diff --git a/pyproject.toml b/pyproject.toml
index aa2590b..70fa9f2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -5,7 +5,7 @@ description = "A tool to sync webdav files (only PDF) to the reMarkable cloud"
 authors = ["Jonathan Weth <dev@jonathanweth.de>"]
 
 [tool.poetry.dependencies]
-python = "^3.8"
+python = "^3.7"
 dynaconf = "^3.1.2"
 click = "^7.1.2"
 webdavclient3 = "^3.14.5"
diff --git a/tox.ini b/tox.ini
index 603335e..5027eda 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,7 @@
 [tox]
 skipsdist = True
 skip_missing_interpreters = true
-envlist = py38,py39
+envlist = py37,py38,py39
 
 [testenv]
 whitelist_externals = poetry
@@ -48,7 +48,7 @@ sections = FUTURE,STDLIB,THIRDPARTY,FIRSTPARTY,LOCALFOLDER
 
 [mypy]
 plugins = mypy_django_plugin.main
-python_version = 3.8
+python_version = 3.7
 platform = linux
 show_column_numbers = True
 follow_imports = skip