Future:
- SPF
- SpamAssassin / procmail support
- Additional AUTH methods
- Greylisting
- Verify sender address (domain, corresponding authenticated user)
- Temporarily unavailable (Test mode?)
- Reason for disconnect
- Proper handling of "ReqHELO" and "Unknown command"
- Log outgoing SMTP transactions
- Show delivery thread IDs
- Watchdog for delivery threads
- VRFY?
- Show authenticated user in "Received" headers
- Delivery threads should finish sooner
- Ensure random spool object names
- DNSBL

v0.9u:
- NATIVE LINUX PORT!

v0.9t:
- Option to disable MX lookups
- Separate config files or work directories supplied in parameters
- Process CTRL-C properly to quit from user mode gracefully
- IPv6
- Bind to user-specified IPs
+ Option to add Reply-To header to forwarded e-mails
+ Fix non-RFC-compliant handling of lines starting with dots
+ Fall back to HELO when remote server doesn't support EHLO
- Implement CHUNKING extension
- Implement more proper reactions for non-standard replies and sequence breaking

v0.9s:
+ Change "Client disconnected, and thread exited successfully." to "Client disconnected."
+ Fix "Internal error" bug - this should be a temporary failure
+ Fix bug regarding simultaneous delivery to forwarded mailboxes
+ Fix bug in DNSMX.pas: improper handling of MX precedence values larger than 100
+ Fix bug regarding Policies/Hosts table not being case-insensitive
+ Fix service mode not working when compiled with FPC 2.6.2!
+ Alternate mailbox names with + signs (e.g. "megabrutal+games@domain")
+ Domain-scope mailbox settings
+ Improved Wine compatibility
+ Consistent handling of local/relay spool objects
+ Implement Win64 support
+ Fix PRESHUTDOWN
+ Enforce ASCII printable characters in commands
+ Developer comment for test/debug builds
+ More efficient command-line parsing

v0.9r:
+ Forwarding
+ Show Message-IDs upon receipt
+ Send one cumulative DSN when multiple recipients fail
+ Revise DSN text
+ Add timestamp correction to "Received" headers
+ Append "Original-To" header

v0.9q:
+ FCrDNS verification
+ Reject HEAD and POST requests too
+ Domain-specific mailboxes (virtual hosting)
+ Correct incorrect timezone correction
+ Correct bug in address interpretation
+ Correct bug in spool iteration
+ Write thread IDs in spool objects
+ Append "Return-Path" header

v0.9p:
+ Time-outs in reads
+ Meaningful status codes (in smtp.log)
+ Accept mixed-case commands
+ Correct bug in DNS MX queries
+ NoRelayTo list
+ Log SMTP responses on permanent status changes
+ Don't remember status codes (never needed, only causes confusion)

v0.9o:
+ Disconnect HTTP agents
+ WINE compatibility
+ Accept awkward AUTH LOGIN attempts
+ Correct timestamps
+ Fix memory/handle leak

v0.9n:
+ Alternate port
+ PRESHUTDOWN

v0.9m:
+ Careful threading
+ Hide AUTH feature when no users
+ Add protection against loops
+ Ensure case-insensitive relay routes

v0.9l:
+ ParamCount check!
+ Fully support SIZE parameter
+ Better support for 8BITMIME

v0.9k:
+ MaxAuthAttempts
+ Pipelining