diff --git a/README.md b/README.md
index f3eb5b7..e42ec93 100644
--- a/README.md
+++ b/README.md
@@ -7,10 +7,20 @@ This is an experimental project and is not yet used as part of the OwlBoard stac
 The aim of diagram-parser is to simplify the addition of PIS codes that are not yet in the OwlBoard data source.  The planned implementation is as follows:
 
  - diagram-parser is subscribed to an email inbox (IMAP/POP3)
- - Formatted train-crew schedule cards are sent to the inbox (DOCX format) and loaded by diagram-parser
+ - Formatted train-crew schedule cards are sent to the inbox (DOCX - Maybe PDF alternatively - format) and loaded by diagram-parser
  - List of existing PIS codes is loaded and a list of non-existent codes is compiled (0000-9999)
  - If a code is found both in the diagram and on the list of non-existent codes, a Gitea issue is opened providing details of the code.
  - Once the program has run and extracted only the relavent details, the email is deleted and the file is closed and not stored.
  - The evantual aim is to avoid any manual searching of the DOCX files.
 
-The current process of adding new codes involves being made aware of them face to face, or finding them myself and manually finding and adding them to the data source.
\ No newline at end of file
+The current process of adding new codes involves being made aware of them face to face, or finding them myself and manually finding and adding them to the data source.
+
+## Points to Remember
+
+ - Emails received should be verified.
+   - A pre-authorised key in the subject field, any emails not matching the key should be discarded.
+ - Attachment formats may vary slightly.
+   - The format of the attachment should be checked and any errors handled gracefully.
+
+## Main external dependencies (Expected)
+ - mailbox (https://pypi.org/project/mailbox/)