There is a lot of variety when it comes to International Phonetic Alphabet (IPA) systems for any given language or dialect because the IPA symbols aren't extremely precise. Historically, some publishers chose an IPA that was less accurate but more readable, while other publishers chose an IPA that was more accurate but less readable.
We decided to go with an IPA that is more accurate than the average. For Received Pronunciation, we're pretty similar to Oxford's transcriptions here:
We were tempted to go with CUBE's transcriptions, but our linguist suggested that they're so weird that we'd confuse a lot of students.
Any changes to Oxford have to do with us getting a little more accurate.
Let's look at Gabe explain about our IPA as only he can: