From f4f30b855eb4d7ddfdab374fe35eb63ef51a4077 Mon Sep 17 00:00:00 2001
From: jos <wjosdejong@gmail.com>
Date: Thu, 28 Dec 2017 17:11:14 +0100
Subject: [PATCH] Updated history

---
 HISTORY.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/HISTORY.md b/HISTORY.md
index 647cee35f..05211f337 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,5 +1,10 @@
 # History
 
+## 2017-12-28, version 3.18.1
+
+- Fixed #998: An issue with simplifying an expression containing a subtraction.
+  Thanks @firepick1.
+
 
 ## 2017-12-16, version 3.18.0