This one we cannot answer and depends on FXCM unfortunately. We are not affiliated with FXCM so we cannot answer this on their behalf. However, we can say it is not the best practice in the field of Software Development to make a breaking change that is not backward compatible and it would be of poor choice of FXCM to do so, although it is a possibility.
If this was to happen, not only work MooMooForex’s products be impacted, but all indicators and strategies would be impacted. MooMooForex will strive to update their products as quickly as possible if such as situation does arise.