Good news, Ryan Petri updated Activator beta 1.9.4-beta1 which is now compatible with iOS 8.4 Jailbreak. Here it is the beta and not of the public version which should not be waiting too long.
If you want to take advantage of new gestures now, add the source of Ryan http://rpetri.ch/repo from the tab ‘Source’ in Cydia.
Once added, you will be able to install this version and set your favorite gestures to create shortcuts or others. Activation beta also brings some bug fixes. At the moment we have no problems to him on iPhone iOS 6 Plus 8.4.
If you have not already jailbroken your device, here are our two tutorials: