diff --git a/src/ec_date.erl b/src/ec_date.erl
index c894e83..49266b1 100644
--- a/src/ec_date.erl
+++ b/src/ec_date.erl
@@ -101,7 +101,7 @@ parse(Date, Now) ->
     do_parse(Date, Now, []).
 
 do_parse(Date, Now, Opts) ->
-    case filter_hints(parse(tokenise(uppercase(Date), []), Now, Opts)) of
+    case filter_hints(parse(tokenise(string:uppercase(Date), []), Now, Opts)) of
         {error, bad_date} ->
             erlang:throw({?MODULE, {bad_date, Date}});
         {D1, T1} = {{Y, M, D}, {H, M1, S}}
@@ -709,12 +709,6 @@ pad6(X) when is_integer(X) ->
 ltoi(X) ->
     list_to_integer(X).
 
--ifdef(unicode_str).
-uppercase(Str) -> string:uppercase(Str).
--else.
-uppercase(Str) -> string:to_upper(Str).
--endif.
-
 %%%===================================================================
 %%% Tests
 %%%===================================================================
diff --git a/src/ec_git_vsn.erl b/src/ec_git_vsn.erl
index 8c2376f..d690d1a 100644
--- a/src/ec_git_vsn.erl
+++ b/src/ec_git_vsn.erl
@@ -94,22 +94,11 @@ parse_tags(Pattern) ->
         "fatal: " ++ _ ->
             {undefined, ""};
         _ ->
-            Vsn = slice(Tag, len(Pattern)),
-            Vsn1 = trim(trim(Vsn, left, "v"), right, "\n"),
+            Vsn  = string:slice(Tag, string:length(Pattern)),
+            Vsn1 = string:trim(string:trim(Vsn, leading, "v"), trailing, "\n"),
             {Tag, Vsn1}
     end.
 
--ifdef(unicode_str).
-len(Str) -> string:length(Str).
-trim(Str, right, Chars) -> string:trim(Str, trailing, Chars);
-trim(Str, left, Chars) -> string:trim(Str, leading, Chars).
-slice(Str, Len) -> string:slice(Str, Len).
--else.
-len(Str) -> string:len(Str).
-trim(Str, Dir, [Chars|_]) -> string:strip(Str, Dir, Chars).
-slice(Str, Len) -> string:substr(Str, Len + 1).
--endif.
-
 -ifdef(TEST).
 -include_lib("eunit/include/eunit.hrl").
 
diff --git a/src/ec_talk.erl b/src/ec_talk.erl
index 7cacf2a..9b9a71a 100644
--- a/src/ec_talk.erl
+++ b/src/ec_talk.erl
@@ -127,7 +127,7 @@ ask_convert(Prompt, TransFun, Type,  Default) ->
                                                            Default ->
                                                                [" (", io_lib:format("~p", [Default]) , ")"]
                                                        end, "> "])),
-    Data = trim(trim(io:get_line(NewPrompt)), both, [$\n]),
+    Data = string:trim(string:trim(io:get_line(NewPrompt)), both, [$\n]),
     Ret = TransFun(Data),
     case Ret of
         no_data ->
@@ -197,14 +197,6 @@ get_string(String) ->
             no_clue
     end.
 
--ifdef(unicode_str).
-trim(Str) -> string:trim(Str).
-trim(Str, both, Chars) -> string:trim(Str, both, Chars).
--else.
-trim(Str) -> string:strip(Str).
-trim(Str, Dir, [Chars|_]) -> string:strip(Str, Dir, Chars).
--endif.
-
 %%%====================================================================
 %%% tests
 %%%====================================================================