diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 80b511a..fe917f0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,8 +15,8 @@ jobs:
     strategy:
       matrix:
         python-version:
-          - '3.7'
-          - '3.10'
+          - '3.8'
+          - '3.12'
     steps:
       - name: 'Set up Python ${{ matrix.python-version }}'
         uses: actions/setup-python@v5
@@ -32,6 +32,6 @@ jobs:
     steps:
       - uses: actions/setup-python@v5
         with:
-          python-version: '3.10'
+          python-version: '3.12'
       - uses: actions/checkout@v4
       - uses: pre-commit/action@v3.0.1
diff --git a/README.md b/README.md
index 93d09f6..0812820 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 [![codecov](https://codecov.io/gh/valohai/laituri/branch/master/graph/badge.svg)](https://codecov.io/gh/valohai/laituri)
 
 `laituri` is a set of Docker-related Python snippets used at [Valohai](https://valohai.com/).
-You can use it with Python >= 3.7.
+You can use it with Python >= 3.8.
 
 ## Usage
 
diff --git a/laituri/docker/credential_manager/docker_v1.py b/laituri/docker/credential_manager/docker_v1.py
index 0fd8d5c..9ee5bb7 100644
--- a/laituri/docker/credential_manager/docker_v1.py
+++ b/laituri/docker/credential_manager/docker_v1.py
@@ -58,7 +58,7 @@ def docker_login(domain: str, username: str, password: str) -> bool:
     log.debug(f"Running `{' '.join(args)}`")
     proc = subprocess.Popen(args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
     try:
-        cmd_input = (password + '\n').encode('utf-8')
+        cmd_input = f"{password}\n".encode('utf-8')
         stdout, _ = proc.communicate(input=cmd_input, timeout=settings.DOCKER_TIMEOUT)
     except subprocess.TimeoutExpired as te:
         raise DockerLoginFailed('timed out') from te
diff --git a/pyproject.toml b/pyproject.toml
index 5ff1c95..4bca66c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,7 @@ dynamic = ["version"]
 description = "Docker Toolkit for Python"
 readme = "README.md"
 license = "MIT"
-requires-python = ">=3.6"
+requires-python = ">=3.8"
 authors = [
     { name = "Valohai", email = "hait@valohai.com" },
 ]
@@ -45,7 +45,7 @@ strict = true
 exclude = "laituri_tests/test_.*"
 
 [tool.ruff]
-target-version = "py37"
+target-version = "py38"
 line-length = 120
 
 [tool.ruff.lint]
@@ -59,6 +59,7 @@ select = [
     "I", # isort
     "T", # debugger and print
     "TID", # flake8-tidy-imports
+    "UP", # pyupgrade
     "W", # pycodestyle
 ]
 ignore = []