Hi Cash
My understanding of it is that 'con notes' is an abbreviation of the term convertible notes. These are are loans that can be converted into shares at a set date and for a set price (usually a discount). What some HC posters are angry about is that the company is proposing to change the terms of these convertible notes, and in doing so is not really sending a positive message to the market.
All IMO.
Chilloutman