How to put mod enderstorage in gzip format?

My Minecraft server has worked before but has suddenly stopped and the console says that enderstorage is not in gzip format, I have done some research and people seem to be saying that I need to reinstall enderstorage but how do I install a single mod when I am using a modpack(the 1.7.10 pack) I would prefer a method which would mean I do not have to delte any sort of data(enderstorage data is fine)
Thanks in advance

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