Those waiting for a Lumia Flagship announcement in near future are in for some disappointment, if report from our trusted sources needs to be taken into account. It seems, there are no Lumia Flagships worth their name planned before early fall, 2015.
September / October will be really busy for Microsoft and Windows Phone, as Windows 10 may get RTMed and first devices running Windows (Phone) 10 may get launched. Two of these devices are tipped to be Lumia 930 and Lumia 1520 successors.
Lumia 930 successor may come with a 5-inch display and may run on Snapdragon 805 / 810 processor. It will have good flagship specs to boast off.
Lumia 1520 successor may or may not have a full 6-inch display and it will be comparable to Lumia 930 successor in specs department.
There will be other Lumia device launches before these two though in 2015 and at least two of them are expected to be unveiled at MWC 2015. One of them is a Lumia 1320 successor, which can come as Lumia 1330. We have seen some leaks of this device already. It was found in Adduplex database as RM-1062 and family and in a leaked image from China.