If you've been subscribed to one of AT&T's old unlimited data plans for more than a few years, you've probably been subject to a few price increases over time.

Indeed, these grandfathered data plans saw their first price increase in 2015 when AT&T bumped up the monthly fee to $35 from $30. More recently, in 2017, the company did the same thing, raising the cost from $35 to $40.

Now, prices are increasing yet again, by another $5 for a total of $45, as spotted by MacRumors.

This is still a better price than users would pay for one of AT&T's recently-revamped "Unlimited Choice" and "Unlimited Plus" data plans, which cost $65 and $80, respectively.

However, these more frequent price bumps will undoubtedly frustrate users who have become used to paying the same amount for their data plan every month.

AT&T explained their decision in a statement:

Consumers are using mobile data at record levels and the trend is expected to continue. To help make sure we continue to provide the best service for all of our customers, a small price increase is being made at this time.

Customers who have a grandfathered $40 data plan will receive notifications of a $5 per month rate increase for the data plan. The rate increase will take effect starting with the customer's July, 2018 service.

AT&T claims they won't be making any other changes to the way the grandfathered plans work. Data speeds will not be altered; users will still only have their speeds throttled when they exceed 22GB of data during any given month, or if they happen to be in a "congested" area.

The $5 price increase for AT&T's old data plans will be going into effect sometime in July.