What changed
In Codex, Free and Go users got GPT-5.6 Terra, while Plus, Pro, Business and Enterprise could pick Sol, Terra or Luna and set an effort level for each. A new max effort setting and an ultra mode that runs four agents in parallel (Plus and higher) arrived with it. Launch API prices per million tokens were $5 / $30 for Sol, $2.50 / $15 for Terra and $1 / $6 for Luna. The rollout took about 24 hours.
Who it affects
All Codex users, especially Plus and higher choosing between tiers.
What to do
Use Terra or Luna for routine work and keep Sol with max or ultra for hard problems, since ultra uses many more tokens.