diff --git a/ale_linters/python/flake8.vim b/ale_linters/python/flake8.vim
index 14b67d77..b5b5f3cc 100644
--- a/ale_linters/python/flake8.vim
+++ b/ale_linters/python/flake8.vim
@@ -89,7 +89,7 @@ function! ale_linters#python#flake8#Handle(buffer, lines) abort
     " Matches patterns line the following:
     "
     " stdin:6:6: E111 indentation is not a multiple of four
-    let l:pattern = '\v^[a-zA-Z]?:?[^:]+:(\d+):?(\d+)?: ([[:alnum:]]+) (.*)$'
+    let l:pattern = '\v^[a-zA-Z]?:?[^:]+:(\d+):?(\d+)?: ([[:alnum:]]+):? (.*)$'
     let l:output = []
 
     for l:match in ale#util#GetMatches(a:lines, l:pattern)
diff --git a/test/handler/test_flake8_handler.vader b/test/handler/test_flake8_handler.vader
index cdf20bc0..fe42211a 100644
--- a/test/handler/test_flake8_handler.vader
+++ b/test/handler/test_flake8_handler.vader
@@ -258,3 +258,19 @@ Execute(E112 should be a syntax error):
   \ ale_linters#python#flake8#Handle(bufnr(''), [
   \   'foo.py:6:1: E112 expected an indented block',
   \ ])
+
+Execute(Compatibility with hacking which uses older style flake8):
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 6,
+  \     'col': 1,
+  \     'vcol': 1,
+  \     'code': 'H306',
+  \     'type': 'W',
+  \     'text': 'imports not in alphabetical order (smtplib, io)',
+  \   },
+  \ ],
+  \ ale_linters#python#flake8#Handle(bufnr(''), [
+  \   'foo.py:6:1: H306: imports not in alphabetical order (smtplib, io)',
+  \ ])