Pip Review 2024. Awarded higher rates, will it be back paid and from when?

Hi, I put in for a review in November and have had my assessment and a decision made, I am waiting on the letter and report to be delivered but I know from the automated service that award was made higher as the next payment is significantly higher.. as I requested the review, and it was accepted, will I have money then owed to me? And also how is it worked out? Will I receive the new rate backdated from the date I put in the request ? Baring in mind they have been paying me my regular amount during this time. So would they just pay me what makes up the difference between old rate and new rate?