diff --git a/runtime/filetype.vim b/runtime/filetype.vim
index 9daf5a3..aa33b65 100644
--- a/runtime/filetype.vim
+++ b/runtime/filetype.vim
@@ -1961,6 +1961,9 @@
 au BufNewFile,BufRead *.zig			setf zig
 au BufNewFile,BufRead *.zir			setf zir
 
+" Zserio
+au BufNewFile,BufRead *.zs			setf zserio
+
 " Z-Shell script (patterns ending in a star further below)
 au BufNewFile,BufRead .zprofile,*/etc/zprofile,.zfbfmarks  setf zsh
 au BufNewFile,BufRead .zshrc,.zshenv,.zlogin,.zlogout,.zcompdump setf zsh
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index 8a38fb7..a704fb6 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -801,6 +801,7 @@
     zimbu: ['file.zu'],
     zimbutempl: ['file.zut'],
     zir: ['file.zir'],
+    zserio: ['file.zs'],
     zsh: ['.zprofile', '/etc/zprofile', '.zfbfmarks', 'file.zsh',
           '.zcompdump', '.zlogin', '.zlogout', '.zshenv', '.zshrc',
           '.zcompdump-file', '.zlog', '.zlog-file', '.zsh', '.zsh-file',
diff --git a/src/version.c b/src/version.c
index 5ad3b34..14ede7f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1645,
+/**/
     1644,
 /**/
     1643,