diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index dd453758..f8a22da3 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -84,7 +84,7 @@ jobs:
     # there's some overlap with publish-pages.yml, but this one runs on pull
     # requests, doesn't publish, and runs more doc checks
     name: docs
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
 
     steps:
       - name: Git clone
diff --git a/doc/install.txt b/doc/install.txt
index f4d65071..dfb62d30 100644
--- a/doc/install.txt
+++ b/doc/install.txt
@@ -96,18 +96,21 @@ First, install the required software.
 5. Python dnspython package from https://pypi.org/project/dnspython/
 
 6. *Optional, build time only, for translations:*
-   polib Python module from https://pypi.org/project/polib/
+   Python polib package from https://pypi.org/project/polib/
 
 7. *Optional, for bash-completion:*
-   argcomplete Python module from https://pypi.org/project/argcomplete/
+   Python argcomplete package from https://pypi.org/project/argcomplete/
 
 8. *Optional, for displaying country codes:*
-    GeoIP from https://pypi.org/project/GeoIP/
+   Python GeoIP package from https://pypi.org/project/GeoIP/
 
-9. *Optional, used for Virus checking:*
+9. *Optional, for reading PDF files:*
+   Python pdfminer.six package from https://pypi.org/project/pdfminer.six/
+
+10. *Optional, used for Virus checking:*
     ClamAv from https://www.clamav.net/
 
-10. *Optional, to run the WSGI web interface:*
+11. *Optional, to run the WSGI web interface:*
     Apache from https://httpd.apache.org/
     mod_wsgi from https://pypi.org/project/mod-wsgi/
 
diff --git a/pyproject.toml b/pyproject.toml
index 41d22d40..c4be6685 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,7 +21,7 @@ classifiers = [
 requires-python = ">=3.7"
 
 dependencies = [
-    "requests >= 2.19",
+    "requests >= 2.20",
     "dnspython >= 2.0",
     "beautifulsoup4 >= 4.8.1",
 ]
diff --git a/requirements-min.txt b/requirements-min.txt
index b2b2f144..5cf3e824 100644
--- a/requirements-min.txt
+++ b/requirements-min.txt
@@ -1,6 +1,7 @@
 # required:
 beautifulsoup4 == 4.8.1
-requests == 2.19.0
+requests == 2.20.0
 dnspython == 2.0.0
 # optional:
 argcomplete == 1.8.1
+pdfminer.six == 20181108
diff --git a/requirements.txt b/requirements.txt
index c12f5530..c869cc03 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,7 @@
 # required:
 beautifulsoup4 >= 4.8.1
-requests >= 2.19
+requests >= 2.20
 dnspython >= 2.0
 # optional:
 argcomplete >= 1.8.1
+pdfminer.six >= 20181108
diff --git a/tox.ini b/tox.ini
index c4a414a9..eff1a51c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,7 +5,6 @@ envlist = py3{7,8,9,10,11}, minreqs
 deps =
     pyftpdlib
     parameterized
-    pdfminer.six
     pyopenssl
     pytest-xdist
     pytest-cov