f add note about corrupt reads in 0.0.100

Author: TheBlueMatt

CHANGELOG.md

@@ -68,6 +68,11 @@
    handle the long hangs in Bitcoin Core when it syncs to disk (#1090).
 
 ## Serialization Compatibility
+ * Due to a bug in 0.0.100, `Event`s written by 0.0.101 which are of a type not
+   understood by 0.0.100 may lead to `Err(DecodeError::InvalidValue)` or corrupt
+   deserialized objects in 0.100. Such `Event`s will lead to an
+   `Err(DecodeError::InvalidValue)` in versions prior to 0.0.100. The only such
+   new event written by 0.0.101 is `Event::ChannelClosed` (#1087).
  * Payments which were initiated in versions prior to 0.0.101 may still
    generate duplicate `PaymentSent` `Event`s or may have spurious values for
    `Event::PaymentPathFailed::all_paths_failed` (#1053).