Long Term Visa Process (Phnom Penh)

Hi everyone..

I will be leaving in Phnom Penh for a few month starting from mid April and I was wondering how can resolve the long term visa issue.

As far as I check from the posts in the forum, 1 year multiple entry visa can be obtained in the airport from immigration office for something like Protected content with no extra documents being required.

Could pls onfirm or correct me if I am wrong?:)

Thanks you very much in advance for sparing your time..