Do ISPs announce every major filtering change?

No, ISPs do not announce every major filtering change. Most algorithmic updates occur silently as models retrain and weights adjust. Only significant policy changes typically receive formal announcement, leaving many impactful changes undisclosed.

This opacity is intentional, preventing spammers from immediately adapting to specific changes. Detailed announcements would provide roadmaps for evasion. Providers balance transparency with effectiveness by sharing policy direction while keeping implementation details private.

Monitor your own deliverability continuously rather than relying on announcements to understand changes. Unexplained metric shifts may indicate filtering changes worth investigating. Community discussions often surface patterns that individual observation might miss.