For the time being, but they might still be required to switch eventually. I wouldn't hold it off too long if wanting to apply there. Anytime in October seems safe but who knows, they might switch over in November or December?
Phnom Penh is in Cambodia and no, it's for everyone. If you need to apply for a visa in Cambodia, the last day is next Friday. After that you can only apply via the evisa portal (beginning the Tuesday after that).