v6.9.0

• Required HTTParty 0.24.0 or later to exclude versions affected by CVE-2025-68696 (potential SSRF and API key leakage)
• Treat 207 Multi-Status responses as successful, so a response that carries partial results is returned instead of raising an error
• Documented tracking_options.domain_name hash support for custom link and open tracking hostnames. See the message tracking documentation
• Documented Contact metadata and metadata_pair hashes, and added contact.updated and contact.deleted webhook trigger constants
• Updated CI runner images and SDK reference documentation deployment, made Ruby 3.0/3.1/3.2 versions explicit, and added gem builds to the Ruby test matrix
• Corrected gem metadata and SDK reference links, and included the changelog, README, and license in the gem package
• Updated the local test command to match the supported Ruby 3.0+ test suite
• Declared the RDoc development dependency so SDK reference documentation also builds on Ruby 4.0, and verified documentation output in CI
• Required YARD 0.9.44 or later for development to exclude known documentation server path traversal vulnerabilities
• Updated the coverage formatter for compatibility with current REXML releases

Full changelog: v6.8.1...v6.9.0