Version 1.0 of the Trailer iOS app is configured and built as an iPhone only application.
During development, I built the app as a 'universal' application (i.e. one which works on both iPhone and iPad, and which intelligently sizes UI pages to take advantage of the available space on the device it is on). I did some testing with this in the iPad mode of the iOS debugger, but at that time I didn't have access to a physical iPad, and I didn't want to encourage people to buy it for that platform until I had an opportunity to verify whether the app was useful on a WiFi-only iPad. My original testing showed that the existing user interface rendered reasonably well in the simulator, so I am not expecting any problems with the basic annotated map behaviour, however the simulator is no help in judging experience in relation to the location services-related features, in particular the feature of providing an alert notification when the app is in the background and the user enters a zone on the currently displayed map (see the second last paragraph of the page 'Using the Trailer iOS application' for details of how this is supposed to work).
I have now lashed out and bought a retina iPad (WiFi only) for development work, and have confirmed that, providing the iPad is tethered to an iPhone via Bluetooth, the background notifications for zone entry work reasonably well. On an iPhone, in my usual test area (which is a public open space), crossing the border into a 200m zone, I generally get a notification from the background at a point which appears visually to be bang on the border if by bring the app up (as the notification allows me to do). On the tethered WiFi iPad, the notification tends to arrive when I am 20-30 metres inside the zone border, which is consistent with the fact that the zone of uncertainty displayed around the current position is of the same order of magnitude. Note that I haven't done any testing yet using tethering between an iPhone and the iPad over WiFi, nor between the iPad and non-iOS smartphones, however I did do some testing a while ago using an iPod touch tethered by WiFi to an Android phone, and found that in this combination I didn't get any background notifications at all while the tethering was turned on.
Anyway, the washup from this is that I am now confident that it is worth offering Trailer on iPad and I plan to do a release in the near future (no specific date promises today) which will be available as a free update from v1.0 of the Trailer app and which will be built as a 'universal' application, i.e. a single app which will work on both iPhone and iPad. I will probably also try to configure this app build so that it is available on iPod Touch devices (depending to some extent on the outcome of future testing). In the mean time, the iPhone version of Trailer still works perfectly well on the iPad in the iPhone compatibility mode (i.e. it can be displayed initially in the middle of the screen in an iPhone-sized area, but can be doubled up to use most of the screen, but will not exploit the resolution available).
Please get in touch with me via the comments on this blog entry if you have concerns or issue reports about the behaviour of the present version of the app (either on the iPhone or the iPad). Alternately, you can visit the app's page in the iOS App Store and mail me via the application support email link there (I don't want to mention the email address on this page as this address is still running with relatively low levels of spam).
