Comcast continued its gradual rollout of internet speed upgrades, doubling the downstream speeds of two of the more popular tiers of Xfinity service in Arkansas, Indiana, and Michigan, at no cost.

The speed upgrades apply to the Blast! and Extreme 50 plans. The company said it will increase the speed of its Performance plan by more than 60 percent in April.

The speed upgrades in these markets in the Midwest follow similar Internet service improvements provided through most of Comcast’s Northeast systems last summer.

With the Blast! plan, Comcast is increasing download rates for customers in Arkansas, Indiana, and Michigan from a maximum of 25 Mbps to up to 50 Mbps, and upload speeds from a maximum of 4 Mbps to up to 10 Mbps.

Extreme 50 customers will get maximum download speeds of up to 105 Mbps, up from 50 Mbps,  and upload speeds of up to 20 Mbps, up from 15 Mbps.

The Performance plan will be increased from 15 Mbps to 25 Mbps on the downstream, and from 2 Mbps to 5 Mbps on the upstream.

To activate the new speeds when they become available, customers just need to re-start their cable modems, the MSO said.

The company completed its upgrade of its network technology to DOCSIS 3.0 -- the technology upon which the speed upgrades are dependent -- last year. The company still has more markets where it has yet to roll out speed upgrades, but declined to comment on the schedule for providing speed upgrades for those markets.