How will IFRS 15 Revenue from Contracts with Customers impact the software industry?

The International Accounting Standards Board (IASB) published IFRS 1 Revenue from Contracts with Customers in May 2014 effective for reporting periods commencing on or after 1 January 2018.  Since IFRS 15 replaces all the existing guidance on revenue recognition and applies to all entities and industries, there has been considerable confusion (and debate) as to what the likely impacts are going to be across different industries when adopted.