According to rumours, the Lumia 930 will be similar to the Lumia Icon / 929 but for GSM networks and possibly with a 4.5″ screen instead of a 5″ one. The Lumia 630/635 will succeed the Lumia 620 and offer slightly higher-end specs than the 525, including dual-SIM (WP8.1 is supposed to add support for it).
Nokia announced its Android-powered phones at the Mobile World Congress, but the rumoured Lumia 930 and Lumia 630/635 were nowhere to be seen. Nokia might be saving those for a separate event on April 19.
News of the event comes from popular rumour source @evleaks. The date might not be a coincidence – two weeks earlier, Microsoft will be holding the BUILD conference. It is expected to bring Windows Phone 8.1 with the Cortana virtual assistant and Start screen backgrounds.