diff --git a/README.mkd b/README.mkd
index ae19c6f..f6b9e9a 100644
--- a/README.mkd
+++ b/README.mkd
@@ -135,6 +135,8 @@ let g:gitgutter_realtime = 0
 let g:gitgutter_eager = 0
 ```
 
+Note the realtime updating requires Vim 7.3.105 or higher.
+
 
 ### Customisation
 
diff --git a/plugin/gitgutter.vim b/plugin/gitgutter.vim
index 0251b6e..528d141 100644
--- a/plugin/gitgutter.vim
+++ b/plugin/gitgutter.vim
@@ -5,6 +5,12 @@ let g:loaded_gitgutter = 1
 
 " Initialisation {{{
 
+" Pre-requisites.
+if v:version < 703 || (v:version == 703 && !has("patch105"))
+  let g:gitgutter_realtime = 0
+  echom "vim-gitgutter: realtime sign updates disabled (requires Vim 7.3.105+)."
+endif
+
 function! s:set(var, default)
   if !exists(a:var)
     if type(a:default)