diff --git a/HISTORY b/HISTORY
index 9fd5d65..091a61f 100644
--- a/HISTORY
+++ b/HISTORY
@@ -19,6 +19,14 @@ HISTORY
   Where applicable, changes are attributed to the people who submitted
   the ideas and, in many cases, patches and source code.
 
+ * Version 4.5.1  (19 Jan 2021)
+   + Documentation updates:
+   + HISTORY moved to separate file from README
+   + README reformatted as Markdown and renamed README.md
+   + description rewritten in README and man page
+   + remove old "porting" section
+   + remove old "things to be aware of" section
+
  * Version 4.5  (7 Dec 2020)
    + handle screen size changes with RANDR, so "xlbiff -bottom"
      stays at screen bottom
diff --git a/configure.ac b/configure.ac
index 19040d1..af5270a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-AC_INIT([xlbiff], [4.5], [ed@edsantiago.com])
+AC_INIT([xlbiff], [4.5.1], [ed@edsantiago.com])
 AM_INIT_AUTOMAKE(foreign)
 AM_MAINTAINER_MODE(enable)
 AC_PROG_CC