ProtocolHistory

Hotline Protocol

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Core Documentation

• Documentation Home
• Glossary / Terms
• Protocol History

Technical Specifications

• Transaction IDs
• Field Definitions
• Access Bits
• Error Codes

Binary & Data

• FILP/RFLT Specs
• News Headers
• Logic Sequences

External Networking

• Tracker (HTRK)
• HTTP Tunneling
• Global Server

Assets

• Icon Gallery

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Protocol Evolution: 1.23 to 1.9

The Hotline protocol underwent significant internal changes as it scaled from a small hobbyist tool to a professional-grade communication suite.

The 1.2x Era (Legacy Basics)

The 1.23 protocol was the "foundation." It established the core TRTP handshake and the concept of Big-Endian binary headers.

• Features: Basic Chat (Trans 105), Messaging, and flat File lists.
• Limitations: Very limited permission sets and no news threading.
• Key Header: The early headers were often shorter and lacked the flexibility for complex sub-parameters seen in later versions.

The 1.5x Era (The "News" Revolution)

Around April 1999, the protocol underwent a major shift, specifically in how News was handled.

• Introduction of Bundles: Version 1.5 introduced Field 323 (News Category List Data), allowing servers to group news into folders (Bundles) rather than just a flat list.
• The GUID Shift: This era saw the introduction of Global Unique Identifiers for news categories to prevent conflicts during server synchronization.
• Banner Support: Version 1.5 introduced the logic to request banners (Trans 122) via HTTP or binary transfer.

The 1.8x - 1.9 Era (The Modern Standard)

This version is what most modern clients and your current wiki documentation focus on. It refined the protocol for high-traffic environments.

• Advanced Permissions: The 64-bit Access Bitmap was fully fleshed out, adding granular control over things like "News Delete Category" and "View Drop Boxes."
• Flattened File Objects (FILP): The file transfer logic was finalized to support cross-platform metadata (INFO vs DATA forks), allowing Mac and Windows users to exchange files with their respective metadata intact.
• Enhanced Login (Version 151): The login sequence was updated to include mandatory Agreement checks (Trans 109/121) and community-driven Banner IDs.

Comparison Table

Feature	v1.23	v1.5	v1.8/1.9
Login Sequence	Direct	Added Banner Req	Agreement/Handshake Req
News Layout	Flat Category	Nested Bundles	Full Threading support
Permissions	Basic (16-bit)	Expanded (32-bit)	Modern (64-bit)
File Transfers	Raw Stream	Added Resume support	FILP/RFLT Standardized