This free update has many improvements, but the key one is taking advantage of the additional screen space on the iPad. You can now permanently show the paper tape, RPN stack, and memories onscreen in a new sidebar area. This was the number one requested feature from iPad users, and we're happy to be able to add it now.
The tape, stack, and memories have had a complete overhaul for the iPhone and iPod touch too, and are now easier to read across all devices, appropriately themed, and with enhanced email support.
PCalc is distributed as a universal app - one purchase will work on iPad, iPhone, and iPod touch. No need to buy a separate "HD" version. It requires an iPhone or an iPod touch running OS 3.0 or later, or an iPad running OS 3.2 or later.