[6][8] High Energy Materials Research Laboratory (HEMRL) developed a new formulation of composite propellant that is more efficient and provide greater thrust compare to Agni missile series.

[2][7] With a shorter range than K-4 missiles it is to be integrated with Arihant class submarine concurrently developed for the use of Indian Navy.

The last development test of the missile occurred on 28 January 2013, from an underwater launch platform off the coast of Visakhapatnam.

[21] India successfully test fired the 3,500 km strike range nuclear-capable K-4 submarine-launched ballistic missile off the coast of Andhra Pradesh on 19 January 2020.

[22][23][24] On 24 January 2020, the final trials were carried out by DRDO in which the missile achieved the near zero circular error probability and hit the target 3,500 km away.

Reportedly, DRDO is in the process of developing a submarine-launched solid fuel missile with a maximum range of 5,000-6,000 kilometres.

It is a three-stage solid fuel multiple independently targetable reentry vehicle (MIRV) capable missile with a length of 12 m, width of 2 m, payload of 2-3 tonne warhead, and a range of 6,000 to 8,000 km.