Cleric Domains Improvement

[Vincent The Dark]

Is there anything that can advance a cleric's domain level? (other than an archetype)
Thanks

[chaoseffect]

Nothing that I have ever seen, barring a few random prestige classes that say they stack with Cleric levels.

[Imbicatus]

If you have another class that has domains - Inquisitor or Druid for example, they stack with cleric for your domain powers.