When loading a default content page or a module that uses the new Filepicker in
IE11 results in a js error:

Object doesn't support property or method 'startsWith'
jquery.cmsms_filepicker.js (79,3)

The Mozilla page at 
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith
provides the following polyfill:

if (!String.prototype.startsWith) {
    String.prototype.startsWith = function(searchString, position){
      return this.substr(position || 0, searchString.length) === searchString;
  };
}

which fixes the issue.

I just added that polyfill to jquery.cmsms_filepicker.js at line 70 but I'll
leave it to you to decide the best location.

Thanks for all your work as usual.

s.