diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 85b4779..46e2fbe 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -1,3 +1,9 @@
+v0.5.0
+- Changed the serialization protocol to sort databases by MI
+- The functionality for the option --mu moved to EPIK
+- Implemented a second database build algorithm: --on-disk for external merge and filtering
+- AR parsers are now on-demand and memory-frugal
+
 v0.4.0
 - The project has been renamed to IPK
 - Serialization and main data structures moved to I2L, changed namespaces
diff --git a/ipk.py b/ipk.py
index 93a2c87..fb884f3 100755
--- a/ipk.py
+++ b/ipk.py
@@ -6,6 +6,7 @@
 
 __author__ = "Nikolai Romashchenko"
 __license__ = "MIT"
+__version__ = "0.5.0"
 
 
 import os
@@ -33,6 +34,7 @@
 
 
 @click.group()
+@click.version_option(__version__)
 def ipk():
     """
     IPK