(November 2021 Verison Update) Composure is not available when Red Mage is set as a Support Job.
The melee accuracy bonus granted is +15 (+7.5% to hit rate, up to a maximum of 95%)
Activating Composure imposes a 25% increase to recast time on all magic, including magic that is not otherwise affected by Composure, and magic that is not classified as white or black magic, such as Songs and Ninjutsu.
Accession and Manifestation recast duration increase is multiplied with that of Composure, for a total multiplier of 3.75.
The duration of most Enhancing Magic spells that you cast on yourself while under this effect are tripled. Enhancing spells cast on other players do not receive this benefit, nor will enhancements cast by other players onto someone with Composure active. However, it is possible for other players to receive a partial extension to their buff duration through the RDM AF3 set effect (see below).
The spells compatible with Composure include the following:
Regen I and II (Regen III, IV, and V cannot be used by a RDM main)
If any spell has an AoE effect, such as a Bar-ra spell like Barfira, or a spell under the effect of Accession, the extended buff will be applied to the caster but not to other players. Again, it is possible for other players to be able to receive a partial extension to their buff duration through the RDM AF3 set effect (see below).
Composure can be manually removed.
Buff duration is determined upon application, meaning that if self-enhancements are cast under Composure and then the Composure effect is removed, the extended duration of the buffs remains.
Composure status is removed by level syncing, zoning, or logging out.
The Composure augmentation from the Estoqueur's Set (RDM AF3) enhances duration of spells cast on others by 10% with 2 pieces equipped, 20% with 3 pieces equipped, 35% with 4 pieces equipped, and 50% for all 5 pieces equipped.