"Dear Sir or Madam" and "Dear Sir/Madam" are binarist and therefore problematic. Not everyone is comfortable being called "Sir" or "Madam".
What is the non-gender-specific equivalent of "Dear Sir or Madam" for a letter salutation, if any? Or, should I ignore the whole issue as well as the advice given by the answers to my original question, and just use "To Whom it May Concern" instead?
For the purposes of this question, assume that the recipient's name, position and other information which could be used in the salutation are not known.