What does "up to 24Mb" mean?

Mb (megabits) refers to the speed at which your broadband can download files.

Okay, but what does "up to" mean?

The speed you'll actually get is down to a number of factors, such as the distance of your line from the exchance, and the quality of the copper line itself. In addition:

1. If your line supports Enhanced Broadband, you’ll get the fastest broadband speed your landline can support, up to a maximum of 24Mb. What’s more, the speed will be congestion-free, giving you a more consistent broadband speed throughout the day and night. We’ll always provide you with Enhanced Broadband where it’s available in your area.

2. If your line doesn’t yet support Enhanced Broadband, the maximum broadband speed you’ll get will be 7Mb. We are currently expanding our Enhanced Broadband service across the country, and once it’s available on your line, we’ll automatically upgrade you for free.

Vodafone always ensures you get the best possible speed on your phone plan.