4. Invalid Messages

A message is invalid if it does not follow the format described in this document. Implementations MUST treat invalid messages as errors. Specific conditions include:

• Invalid framing indicator value (not 0, 1, 2, or 3)
• Truncation at invalid boundaries
• Field sections or content exceeding 2^62-1 bytes
• Field names not converted to lowercase
• Invalid variable-length integer encoding
• Content terminator in wrong position (indeterminate-length)
• Zero-length field names

An invalid message MUST NOT be processed or forwarded by intermediaries.