Bump version number.
diff --git a/Doc/Makefile b/Doc/Makefile
index 1e51903..6732b64 100644
--- a/Doc/Makefile
+++ b/Doc/Makefile
@@ -67,7 +67,7 @@
# This is the *documentation* release, and is used to construct the file
# names of the downloadable tarballs.
-RELEASE=2.2a3
+RELEASE=2.2a4
PYTHON= python
DVIPS= dvips -N0 -t $(PAPER)
diff --git a/Doc/texinputs/boilerplate.tex b/Doc/texinputs/boilerplate.tex
index 25cbe7b..d63929d 100644
--- a/Doc/texinputs/boilerplate.tex
+++ b/Doc/texinputs/boilerplate.tex
@@ -7,5 +7,5 @@
\date{\today} % XXX update before release!
\release{2.2} % software release, not documentation
-\setreleaseinfo{a3} % empty for final release
+\setreleaseinfo{a4} % empty for final release
\setshortversion{2.2} % major.minor only for software