Bump the version number to 1.9.
diff --git a/build.properties b/build.properties
index 7ac8178..052d972 100644
--- a/build.properties
+++ b/build.properties
@@ -9,7 +9,7 @@
 
 title = XZ data compression
 homepage = https://tukaani.org/xz/java.html
-version = 1.8
+version = 1.9
 debug = false
 
 # sourcever sets --release for javac 9 (or later) or -source and -target for