In very simplified terms, a 'hard fork' occurs where a cryptocurrency's existing programming is changed, resulting in an 'old' and 'new' version of the ...
source https://www.google.com/url?rct=j&sa=t&url=https://hallandwilcox.com.au/cryptocurrency-and-tax-hard-forks/&ct=ga&cd=CAIyGmM2Nzk3ODA2ZWViNjVjODI6Y29tOmVuOlVT&usg=AFQjCNGrAWE1Q8HRjqnk7OZl6ir5ewZWFQ
