diff --git a/README.md b/README.md
index 18c181f..23ec565 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ Most importantly, Lark will save you time and prevent you from getting parsing h
 
 ### Install Lark
 
-    $ pip install lark-parser
+    $ pip install lark-parser --upgrade
 
 Lark has no dependencies.
 
@@ -77,12 +77,11 @@ Notice punctuation doesn't appear in the resulting tree. It's automatically filt
 
 ### Fruit flies like bananas
 
-Lark is great at handling ambiguity. Let's parse the phrase "fruit flies like bananas":
+Lark is great at handling ambiguity. Here is the result of parsing the phrase "fruit flies like bananas":
 
 ![fruitflies.png](examples/fruitflies.png)
 
-See more [examples here](https://github.com/lark-parser/lark/tree/master/examples)
-
+See the code and more [examples here](https://github.com/lark-parser/lark/tree/master/examples)
 
 
 ## List of main features
diff --git a/docs/features.md b/docs/features.md
index 9346989..c2f6983 100644
--- a/docs/features.md
+++ b/docs/features.md
@@ -19,8 +19,8 @@
 [Read more about the parsers](parsers.md)
 
 # Extra features
-
   - Import rules and tokens from other Lark grammars, for code reuse and modularity.
+  - Support for external regex module ([see here](/docs/classes.md#using-unicode-character-classes-with-regex))
   - Import grammars from Nearley.js ([read more](/docs/nearley.md))
   - CYK parser
 
diff --git a/lark/exceptions.py b/lark/exceptions.py
index 645b09c..a844dd4 100644
--- a/lark/exceptions.py
+++ b/lark/exceptions.py
@@ -72,7 +72,11 @@ class UnexpectedInput(LarkError):
 
 class UnexpectedCharacters(LexError, UnexpectedInput):
     def __init__(self, seq, lex_pos, line, column, allowed=None, considered_tokens=None, state=None, token_history=None):
-        message = "No terminal defined for '%s' at line %d col %d" % (seq[lex_pos], line, column)
+
+        if isinstance(seq, bytes):
+            message = "No terminal defined for '%s' at line %d col %d" % (seq[lex_pos:lex_pos+1].decode("ascii", "backslashreplace"), line, column)
+        else:
+            message = "No terminal defined for '%s' at line %d col %d" % (seq[lex_pos], line, column)
 
         self.line = line
         self.column = column