diff --git a/CHANGES.md b/CHANGES.md
index 67649e2ed..4f45e25be 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -8,6 +8,11 @@ Documentation:
 - Update examples for options `bracketedSpans` and `fencedDivs`.
   (499c65a, 532cdb8)
 
+Fixes:
+
+- Map U+0000 to U+FFFD in strings. (lostenderman#34, #247)
+- Map non-breaking space to `writer->nbsp` in strings. (lostenderman#99, #247)
+
 Default Renderer Prototypes:
 
 - Use `paralist` LaTeX package to define default renderer prototypes for
@@ -20,7 +25,8 @@ Default Renderer Prototypes:
 
 Unit Tests:
 
-- Do not fold tabs and spaces into a single space token. (#242)
+- Do not fold tabs and spaces into a single space token.
+  (lostenderman#107, #242)
 
 Speed Improvements:
 
diff --git a/markdown.dtx b/markdown.dtx
index fdab9bb1d..52d225cd8 100644
--- a/markdown.dtx
+++ b/markdown.dtx
@@ -20861,6 +20861,8 @@ function M.writer.new(options)
      ["^"] = "\\markdownRendererCircumflex{}",
      ["~"] = "\\markdownRendererTilde{}",
      ["|"] = "\\markdownRendererPipe{}",
+     [entities.hex_entity('0000')] = entities.hex_entity('FFFD'),
+     [entities.hex_entity('00A0')] = self.nbsp,
    }
 %    \end{macrocode}
 % \par