While the amount of RAM has been steadily increasing in Android flagships, Apple has tended to lag behind where memory and storage was concerned. That might change in the next model which might finally see more RAM.
The argument has always been that iOS is optimised enough that it doesn't need as much RAM as Android, but still considering how much you pay for an iPhone you would expect comparable hardware to Android flagships.
3GB of RAM will certainly be a good boost now that iOS apps are becoming more resource-dependent. The RAM prediciton has been made twice by KGI Securities analyst Ming-Chi Kuo, with DigiTimes also chiming in.
What is pretty certain though is that there will be at least two new iPhone models, one regular and one 'plus' edition. Whether or not the extra RAM will be seen in both phones or just the higher-end model is yet to be ascertained. It could be possible that Apple might reserve more memory for the higher-end model, much like it only implemented OIS in the Plus versions of the iPhone 6 series.
We'll help you keep up with what we know about the latest iPhone so far.