diff --git a/CHANGELOG.md b/CHANGELOG.md
index 480f84e0..4143b388 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,24 +1,40 @@
 # Change log
 
-## 0.9.17 on 2022/08/xx
+## 0.9.18 on 2022/xx/xx
+
+### [Experimental] BIOS mode🛠️
+PRK automatically detects if it's connecting to BIOS and adjusts its behavior.
+
+But it seems not to work depending on the environment.
+We are waiting for feedback from you all! (Tell us your computer model ID)
+
+## 0.9.17 on 2022/08/06
 
 ### Consumer key 🔈🔇🔊
 See [wiki/Consumer key](https://github.com/picoruby/prk_firmware/wiki/Consumer-key)
 
 ### Keyboard#send_key🎛️
 It now accepts multiple keycodes.
-Good for combining with rotary encoders. Check a good example on [wiki/Rotary encoder](https://github.com/picoruby/prk_firmware/wiki/Rotary-encoder).
+Good for combining with rotary encoders. Check an example on [wiki/Rotary encoder](https://github.com/picoruby/prk_firmware/wiki/Rotary-encoder).
 
 ### PRK_DESCRIPTION📝
 Version number, built date, and revision hash are shown on serial console at boot time.
 
 <img src="https://user-images.githubusercontent.com/8454208/181443996-5ee02178-5e10-4196-aed5-5a9eacc62d6a.png" width="300" />
 
-### [Experimental] BIOS mode🛠️
-PRK automatically detects if it's connecting to BIOS and adjusts its behavior.
+### PicoRuby version 3.1🔥
 
-But it seems not to work depending on the environment.
-We are waiting for feedback from you all! (Tell us your computer model ID)
+The programming processing system, PicoRuby, upgraded from 3.0 to 3.1.
+This shouldn't affect any external behavior regarding keyboard (hopefully🤞).
+
+One beneficial thing to users is that the functionality of exceptions improved.
+Let's say you are mistakenly write `kbd = Keyb_oard.new`, not `kbd = Keyboard.new`, an error message will show on the serial console:
+
+<img src="https://user-images.githubusercontent.com/8454208/183228184-04b77485-7de2-4af9-8816-151f919711b6.png" width="300" />
+
+In such a situation, your keyboard doesn't work as a keyboard but the PRKFirmware storage drive keeps alive. Until version 0.9.16, the drive was unexpectedly unmounted and you might have difficulty rewriting your keymap.rb.
+
+Again, we strongly recommend using a serial console when your keymap.rb doesn't work. See [wiki/Debug print](https://github.com/picoruby/prk_firmware/wiki/Debug-print)
 
 ### Bug fix🐛
 - An issue related to "Startup time reduced⌨💨" [issues/120](https://github.com/picoruby/prk_firmware/pull/120)