Add changelog entry
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8fea982..20e6238 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,5 @@
 ## Changes in 0.12:
+- Bug: convertToWrapper expects body to be bytes (#518)
 - Enh: Be more lenient when parsing List-Id headers (#511)
 - Enh: add some debug output to import-mbox (#396)
 - Enh: Allow fetching emails with quotes in their document ID