diff --git a/runtime/syntax/erlang.vim b/runtime/syntax/erlang.vim
index c65ebf3..b8cbf07 100644
--- a/runtime/syntax/erlang.vim
+++ b/runtime/syntax/erlang.vim
@@ -2,7 +2,7 @@
 " Language:     Erlang (http://www.erlang.org)
 " Maintainer:   Csaba Hoch <csaba.hoch@gmail.com>
 " Contributor:  Adam Rutkowski <hq@mtod.org>
-" Last Update:  2019-Jun-18
+" Last Update:  2020-May-26
 " License:      Vim license
 " URL:          https://github.com/vim-erlang/vim-erlang-runtime
 
@@ -44,7 +44,7 @@
 
 " Comments
 syn match erlangComment           '%.*$' contains=erlangCommentAnnotation,erlangTodo
-syn match erlangCommentAnnotation ' \@<=@\%(clear\|docfile\|end\|headerfile\|todo\|TODO\|type\|author\|copyright\|doc\|reference\|see\|since\|title\|version\|deprecated\|hidden\|private\|equiv\|spec\|throws\)' contained
+syn match erlangCommentAnnotation ' \@<=@\%(clear\|docfile\|end\|headerfile\|todo\|TODO\|type\|author\|copyright\|doc\|reference\|see\|since\|title\|version\|deprecated\|hidden\|param\|private\|equiv\|spec\|throws\)' contained
 syn match erlangCommentAnnotation /`[^']*'/ contained
 syn keyword erlangTodo            TODO FIXME XXX contained
 
@@ -92,7 +92,7 @@
 
 " Constants and Directives
 syn match erlangUnknownAttribute '^\s*-\%(\s\|\n\|%.*\n\)*\l[[:alnum:]_@]*' contains=erlangComment
-syn match erlangAttribute '^\s*-\%(\s\|\n\|%.*\n\)*\%(behaviou\=r\|compile\|export\(_type\)\=\|file\|import\|module\|author\|copyright\|doc\|vsn\|on_load\)\>' contains=erlangComment
+syn match erlangAttribute '^\s*-\%(\s\|\n\|%.*\n\)*\%(behaviou\=r\|compile\|export\(_type\)\=\|file\|import\|module\|author\|copyright\|doc\|vsn\|on_load\|optional_callbacks\)\>' contains=erlangComment
 syn match erlangInclude   '^\s*-\%(\s\|\n\|%.*\n\)*\%(include\|include_lib\)\>' contains=erlangComment
 syn match erlangRecordDef '^\s*-\%(\s\|\n\|%.*\n\)*record\>' contains=erlangComment
 syn match erlangDefine    '^\s*-\%(\s\|\n\|%.*\n\)*\%(define\|undef\)\>' contains=erlangComment