RMX effects for recordbox 5 (still able to purchase even with RB6 out?)

Hi there, 

I have no need or want to upgrade to recordbox 6 as all the features that I want and need are on recordbox 5. I just started the trial for the RMX effects and I like them! Is there anyway to get a license for recordbox 5? Every time I click the purchase license button in recordbox 5 software I am greeted with recordbox 6 plans that I do not want. Please tell me how I can pay for a RMX effects license for recordbox 5. Let me stress, I am NOT AT ALL interested in upgrading to recordbox 6. 

Thanks!