diff --git a/README.md b/README.md
index f705dbf..590e5af 100644
--- a/README.md
+++ b/README.md
@@ -194,9 +194,9 @@ A detailed description of these options with examples can be found [here](https:
 
 ## Requirements
 
-- Python >= 3.6
-- [PyNaCl](https://pypi.org/project/PyNaCl/) >= 1.2.0 (provides `Argon2`)
+- Python >= 3.9
 - [PyCryptodomex](https://pypi.org/project/pycryptodomex/) >= 3.6.2 (provides `ChaCha20`)
+- [PyNaCl](https://pypi.org/project/PyNaCl/) >= 1.2.0 (provides `BLAKE2` and `Argon2`)
 
 ---
 
diff --git a/deb/DEBIAN/control b/deb/DEBIAN/control
index 6f71fce..876a2bd 100644
--- a/deb/DEBIAN/control
+++ b/deb/DEBIAN/control
@@ -2,7 +2,7 @@ Package: tird
 Version: 0.16.0
 Section: utils
 Architecture: all
-Depends: python3 (>= 3.6.0), python3-nacl (>= 1.2.0), python3-pycryptodome (>= 3.6.2)
+Depends: python3 (>= 3.9.0), python3-nacl (>= 1.2.0), python3-pycryptodome (>= 3.6.2)
 Maintainer: Alexey Avramov <hakavlad@gmail.com>
 Priority: optional
 Homepage: https://github.com/hakavlad/tird
diff --git a/docs/MANPAGE.md b/docs/MANPAGE.md
index bc2847b..011a478 100644
--- a/docs/MANPAGE.md
+++ b/docs/MANPAGE.md
@@ -149,9 +149,10 @@ Enabling debug messages additionally shows:
 
 # REQUIREMENTS
 
-- Python >= 3.6
-- PyNaCl >= 1.2.0
+- Python >= 3.9
 - PyCryptodomex >= 3.6.2
+- PyNaCl >= 1.2.0
+
 
 # TUTORAL
 
diff --git a/docs/tird.1 b/docs/tird.1
index a532daa..98ff5c2 100644
--- a/docs/tird.1
+++ b/docs/tird.1
@@ -43,37 +43,30 @@ box even if you encrypt files without hiding them in containers.
 .PP
 print debug messages
 .SH INPUT OPTIONS
-.IP \[bu] 2
-[01] Select an action
-.IP \[bu] 2
+.PP
+\f[B]tird\f[R] has the following input options:
+.IP
+.nf
+\f[C]
+[01] Select an option
 [02] Use custom settings?
-.IP \[bu] 2
 [03] Argon2 time cost
-.IP \[bu] 2
 [04] Max padding size
-.IP \[bu] 2
 [05] Set a fake MAC tag?
-.IP \[bu] 2
 [06] Input file path
-.IP \[bu] 2
 [07] Output file path
-.IP \[bu] 2
 [08] Start position
-.IP \[bu] 2
 [09] End position
-.IP \[bu] 2
 [10] Comments
-.IP \[bu] 2
 [11] Keyfile path
-.IP \[bu] 2
 [12] Passphrase
-.IP \[bu] 2
 [13] Proceed?
-.IP \[bu] 2
 [14] Output file size
+\f[R]
+.fi
 .PP
-See <https://github.com/hakavlad/tird/blob/main/docs/INPUT_OPTIONS.md>
-for detailed descriptions and examples.
+For a detailed description of these options, see
+<https://github.com/hakavlad/tird/blob/main/docs/INPUT_OPTIONS.md>.
 .SH GOALS
 .IP \[bu] 2
 Providing protection for individual files, including:
@@ -240,11 +233,11 @@ Development is not complete, there may be backward compatibility issues
 in the future.
 .SH REQUIREMENTS
 .IP \[bu] 2
-Python >= 3.6
-.IP \[bu] 2
-PyNaCl >= 1.2.0
+Python >= 3.9
 .IP \[bu] 2
 PyCryptodomex >= 3.6.2
+.IP \[bu] 2
+PyNaCl >= 1.2.0
 .SH TUTORAL
 .PP
 Step-by-step guides and examples you can see here
diff --git a/pyproject.toml b/pyproject.toml
index 8741d76..ab46674 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -33,7 +33,7 @@ dependencies = [
     "pycryptodomex>=3.6.2",
     "pynacl>=1.2.0",
 ]
-requires-python = ">=3.6"
+requires-python = ">=3.9"
 
 [project.urls]
 "Bug Tracker" = "https://github.com/hakavlad/tird/issues"