Activation authentication mechanism changed in 4.5. Instead of user credentials, the request between author and public instance is now authenticated with a key.

Document the new mechanism in /security/activation and cross reference the article from /editing/activating. Explain the benefits and how it works. Concept Activation Authentication wiki page has details. See new page Tools > Activation in AdminCentral where new public key is generated.

Suggestion for article structure:

• Secure activation, why needed and how Magnolia does it (intro)
• Public key authentication (summarize how key authentication works)
• Generating a new public key
• Copying the key to public instances
• Troubleshooting (when activation workflow fails due to key mismatch), logging

Help text in Tools > Activation says "[key] will be transfered automatically to all configured public instances upon first activation or after generating new key set above". This did not work for me. Had to copy it to public instance manually. Check with Jan how this should work and propose a revised help text if incorrect/confusing.

Wiki page mentions an "alert task in the activation command chain to warn user that secure communication was not yet established". Check status from Jan.