You don't have to retake the test if your English test score is B1 and above. You will only have to retake if the test provider is not included in the list of accepted test providers. I haven't seen any documents that indicate the test will only be accepted twice. My IELTS was taken in 2011. I was also under the old rules. It was accepted for my Fiancee Visa (2011), FLR(M) (2012), ILR (2015) and citizenship (2017).