What do WhatsApp's blue ticks mean?

Thomas Ibingira, a mobile app developer, was chatting using his WhatsApp and all of a sudden he saw blue ticks on one of his messages as opposed to the grey tick that we are all used to.
For years, WhatsApp users have argued over the relevance of the double tick system.
For years, WhatsApp users have argued over the relevance of the double tick system.
Times Reporter