Developer James Thomson reported on Twitter this morning that he's been threatened with patent infringement for his use of in-app purchases in PCalc Lite.

Just got hit by very worrying threat of patent infringement lawsuit for using in-app purchase in PCalc Lite. Legal docs arrived via fedex.

No idea what to do... They seem to be effectively claiming the rights to in-app purchase, but going after me, not Apple.

Talking to Apple now, may go quiet on this for the short term until I know what's happening.

So, have talked to Apple contact - currently scanning everything in to send. Sorry folks, no PCalc 2.4 happening today.

To be clear, I haven't been sued yet - I've been told that I am infringing their patent, they want me to license it, and I have 21 days.

Thomson isn't the lone target of these threats, his UK timezone might just have gotten them to him sooner. Already Patrick McCarron has reported the same thing.

Anyone else get a patent threat via FedEx for in-app purchase use in their iOS app? So far @jamesthomson and I got hit.

I can now check off being threatened by a patent troll off my bucket list.

There are likely other developers who simply haven't chosen to come forward yet. If you've gotten a FedEx patent threat today, let us know.

UPDATE: The company claiming infringement is Lodsys and they seem to be targeting iOS apps that have free/lite versions and full versions, and link to or allow updating within app from free/lite to full. Rob Gloess of Computer LogicX was hit yesterday [MacRumors]

Our app, Mix & Mash, has the common model of a limited free, lite, version and a full version that contains all the features. We were told that the button that users click on to upgrade the app, or rather link to the full version on the app store was in breach of US patent no 7222078, we couldn't believe it, the upgrade button!?!

UPDATE 2: Apparently, according to the iOS SDK license, developers are not allowed to settle these kinds of lawsuits. [TidBITS]

In no event may You enter into any settlement or like agreement with a third party that affects Apple’s rights or binds Apple in any way, without the prior written consent of Apple.

[@jamestomson, @McCarron]

What's your name? James Thomson

What's your company called? TLA Systems - and yes, that does stand for "Three Letter Acronym". It was originally a fake company name I made up with friends to get us into trade shows while we were still students. I kept using it, and now it's a real company employing myself and my wife.

Where are you located? We're based in my native Glasgow, on the west coast of Scotland. It can be a bit dark, cold, and wet, but I wouldn't want to live anywhere else - you need the dark to appreciate the light.

What's your website address? http://www.tla-systems.co.uk/ and http://www.pcalc.com/

What's your Twitter handle? I'm @jamesthomson - that's my personal account, but I tend to use it for work too.

What are some of your apps? Our main app on iOS is the scientific calculator PCalc, which is in turn based on PCalc for Mac OS X. We're also known for DragThing, the dock app that pre-dates Mac OS X.

What other apps do you currently like? NanoStudio is great for writing music on the move - it's more powerful than GarageBand in many ways, and runs on my phone. I'm not really a musician, but I do enjoy tinkering. Shazam still seems like magic to me - it's invaluable for identifying background music on TV and in shops. RedLaser is the best app I've come across for barcode and QR code scanning. The Chambers Dictionary and The Chambers Thesaurus apps are also both very good. I'm also still playing Game Dev Story - it's a game all developers and journalists should play!

How long have you been developing? Almost 20 years - I started programming Macs while I was at university, and have been doing it professionally for at least 16.

How long have you been developing for iOS? Since the very first iPhone SDK was released - three years.

Do you do any mobile development besides iOS? Just the Mac. The two are similar enough that i can keep both in my head at once.

What kind of rig do you use for developing? I do almost all of my development on a 3GHz eight-core Mac Pro with a 24” LG L245WP LCD monitor, and everything else on a very broken white second-generation 2GHz MacBook which needs a complete set of new plastics. Plugged into that currently is an iPad 2, an iPhone 4, and a 2nd-generation iPod touch.

What personal iOS device(s) do you use My iPhone 4 is my main phone, so I use it throughout the day.

Do you use any non-iOS mobile devices? Not sure it counts, but I still have a 4th-generation iPod nano which I use mainly for listening to podcasts and audiobooks when I'm out and about. I like the physical controls, and it doesn't break when I drop it. The iPhone has replaced everything else.

What's your favorite thing about developing for iOS? Well, if I'm honest, I'd say it's the fact that it's possible to make a living doing it! But I think it's having a physical device in my hand - it's a very different feeling to developing for the desktop. And iOS is a very nice platform - more modern than Mac OS X in a lot of ways.

What's your least favorite thing about developing for iOS? It's something of a cliché I know, but it's always the approval process. I certainly agree with it in principle, but it adds a layer of uncertainty which can make submitting apps a very nerve-wracking process. We haven't had any big problems or rejections so far, but I always hold my breath when pushing the button.

What feature would you most like Apple to add to the iOS 5 SDK? It's minor, but I'd like the ability to support hardware keyboards with PCalc - at the moment it's not possible to use a external keyboard with an app that displays its own onscreen keyboard. Actually, the real feature I'd like to see is support for the Apple TV - I'd love to develop a new app for my TV.

What feature would you most like Apple to add to the App Store? As a customer, I'd like to be able to sort by some metric of "quality" rather than just popularity. A lot of apps with really bad reviews stay in the charts for some reason, and I'd like to be able to filter them out. Of course, since PCalc gets a lot of good reviews, that wouldn't hurt me as a developer either!

When something goes wrong while you're coding, what do you say?* I'd like to say that I swear entirely in obscure Scots, but in truth it's all very traditional and Anglo-Saxon. It also depends if I'm on my own in the office...

What do you do when you're not coding iOS apps? I like to get away from computers, but generally don't get too far away from screens in some form. I try to get to the cinema at least once a week, and I play a lot of video games. But my ideal would be to spend time with friends!

What should we look for from you next? A gentleman never tells... I'm currently putting the finishing touches on a small PCalc update for iOS, to be followed by a corresponding Mac update soon after. After that, I'm hoping to select the "New Project..." menu item in Xcode for the first time in a good few years. Like many iOS developers who play games, I keep thinking I could write a small game myself, but that's probably not the best plan given how many other excellent games there are out there!

Thanks James!

James Thomson wrote in to tell us about PCalc 1.7 [$9.99 - iTunes link], and as usual, the prose is almost as good as the app. Almost.

One year ago, as the doors of the iPhone App Store first opened to the public, PCalc was there. One of only four hundred applications available, and a mere handful of calculators. Now, there are more than sixty-five thousand applications in the store, and calculators are second only to Twitter clients in terms of near-pestilential ubiquitousness.

Metaphorgeddon aside, while we mentioned the new version already, after using it for the day, it was obvious it deserved a closer look. Here are the updates again:

• Faster startup!
• Three and four-line display modes, including complete control over what appears on each line.
• Multiple-memory support.
• Optional HP48-style RPN behaviour.
• Much nicer number display with the "Easier To Read" digits option. It's now actually easier to read!

It is indeed. I'm not a mathmagician like Leanna, but this really is the built-in calculator on Hulk-serum. Check out the screenshots after the break, and if you give PCalc 1.7 a try, let us know what you think!

PCalc developer James Thomson is one of our favorites because he not only makes great apps, but he seems to love doing it, and always figures out new, positive, and productive ways to get our attention.

This time around it isn't just the release of an iPhone 3.0 compatible version of PCalc for iPhone ($9.99 - iTunes link) that includes support for copy and paste (and a couple of new vertical button layouts, one for engineers, one for programmers), it's how he built one version of the app that supports both iPhone 2.2.1 and iPhone 3.0 at the same time. An iPhone version of Apple's "universal binary" concept, as it were.

We're not sure he's the first to do this -- and according to Twitter he isn't either -- but we hope he does write up the process when the 3.0 SDK NDA (non-disclosure agreement) lifts so other developers can do it as well. It's an elegant solution to say the least.

Now to see if we can not only paste some complex calculations... but understand them!

Apple's Ad-Hoc iPhone distribution method allows developers to register up to 100 iPhones or iPod touches so they can run their applications on them without having to go through the App Store. This is priceless for beta testing, educational environments, and other non-public environments.

Dragthing's James Thomson, however, has posted on a problem that just might bite a few developers right in their beta tests:

Reading between the lines, and discussions on the forums, it sounds like every time I deleted or modified an entry, I was getting one closer to the magic figure of 100 device IDs you have entered since the beginning of time. When you hit the limit, regardless of how many total device IDs you have listed in the portal, your ability to further edit the list is removed completely.

In other words, if you change your beta testers -- if you change your own device -- you might just end up locked out of your own Ad-Hoc distribution.

Check out the full post for more on this problem and what, if nothing, Apple is currently doing to help developers fix and/or work around it.

Meanwhile, let us know if you have any ideas as well...

The App Store, even with 25,000 applications, is still a new market and one we're all, developers, users, and media alike, trying to figure out. Developer James Thomson recently did an experiment to see how Twitkitteh, a fun little app, would compare in terms of sales and earnings, to his acclaimed PCalc in the App Store.

The results? Thomson talks about them in a blog post entitled Where Did it All Go Wrong?

Since Twitkitteh released about a week ago, we have sold exactly a hundred and one copies, at roughly 99c each. That makes it about £50 in terms of income at current exchange rates after Apple’s 30% cut. About 14 quid of that went on the domain name for a year, and about another 11 quid on hosting the domain on our existing server.

That leaves us £25 profit for three week’s work. Oh, and minus the 120 or so engineer-hours spent designing, writing, and promoting it that could have been spent on something else. So, depending on exactly how much you rate iPhone engineers at on an hourly basis, you can calculate exactly how much we lost on the whole project.

The good news is, with his grand Twitkitteh experiment completed (for now?), PCalc and PCalc Lite have received updates:

PCalc [iTunes link] gets a brand new engineering layout, with hyperbolic trig functions, hypotenuse, leg, gamma, delta percent and more. You also get a classic theme taken from PCalc on Mac OS X, and six new key click sounds you can choose from too.

PCalc Lite [iTunes link] gets just two of the click sounds, and some other small improvements. PCalc Lite remains completely free however, and completely awesome. If you want to get a feel for how the full PCalc works on the iPhone, just try it out.

Here's hoping quality apps like PCalc and others will sell well enough that developers won't have to spend their limited time working on the next great fart app to makes ends meet.

Thanks to James Thomson at Twitkitteh [iTunes link] for helping our awesome readers help their amazing cats express their inner lulz on the Twitter. James was gracious enough to pass along two iTunes App Store Promo Codes for Twitkitteh to two lucky TiPb readers, and without further ado, those are:

• Stephanie Berry
• bas.o

Enjoy. And make sure your kitteh's follow @twitkitteh and @theiphoneblog, b'okay?

We can't tell if twittkitteh (iTunes Link) is shrewd marketing or wicked satire at the state of the App Store and Twitter. We suspect it's equal parts both, finished with a good shot of lulz.

Says developer James Thomson:

Twitkitteh is, quite simply, the first Twitter application written specifically for cats.

For many years, cats have been unfairly excluded from this social networking phenomenon, but we at TLA Systems believe it is finally time to change that.

Designed from the ground up for the iPhone, and featuring a simple multi-paw interface, Twitkitteh allows your cat to post insightful comments to Twitter on a wide variety of subjects - all without the tiresome inconvenience of learning to type first.

Your cat deserves a voice on the Internet, and Twitkitteh is that voice.

Welcome to Cat 2.0.

Brilliant, and what's even more brilliant is he's giving away two (2) copies to our faithful TiPb readers. Just drop a twitkitteh-inspired comment (and be sure to include a real email address, we won't make it public but we will use it to notify you if you win!). Get to it!

(Note: Unfortunately, Promo Codes only work in the US App Store, so if you don't have access, you won't be able to claim a prize.)

James Thomson is the acclaimed developer behind DragThing for Mac OS X and PCalc RPN Calculator for the iPhone and iPod Touch. Following up on his recent blog postings about the challenges involved navigating the still-nascent App Store business model for developers, and TiPb's own look at whether or not there's a "long tail" potential for the market, James was gracious enough to sit down (virtually) and share his thoughts with us about the issues facing 3rd party iPhone developers going forward.

TiPb: James, you recently blogged about PCalc in the context of a "postmortem". What was the reaction like to that article, and did it bring about any changes in your current thinking or how you plan to proceed with PCalc going forward?

James Thomson: Reaction was interesting. Many iPhone developers contacted me privately, and via the blog, to say they had encountered similar problems with sales after the recent changes to the App Store.
Some pointed out the "Availability Trick" to change the App Store release date for your software when you do an update, to make it sort higher up in the listings. I talked about that a bit in a follow-up post here. It's unclear whether it really is a trick, or just what you are supposed to do, but it does seem to work.

I've also tried a few other suggestions, like renaming the app to "PCalc RPN Calculator" to make sure it appears during searches for the word "calculator" which it didn't before. So far, there has been a relatively small boost to sales, but I'm not sure how much of that is due to my changes, and how much is just down to the overall publicity that the article generated.

I'm working on a small 1.1.1 update at the moment to fix a few things, and I'll likely add some more layouts and themes. The real question is what will happen to sales then. If they remain flat, with all the other changes, then I'm going to have to try some more traditional marketing beyond the Google AdWords adverts we are already running. To a certain extent, the blog itself /is/ a form of marketing - I don't think I can really deny that, given it is raising the profile of our software.

Read the rest of the interview after the jump...

TiPb has been looking at the App Store and whether or not there is a "long tail" for developer income. Do you think there is currently a long-term business model for developers of niche-apps?

I think it's a much harder market than it was back in July. It's well publicised that the store is pretty crowded now, and it's getting increasingly harder to find things.

I think that when the App Store launched, the initial sales numbers were so high, that many developers - myself included - ended up with cartoon dollar signs for eyes, multiplying the first few months of sales figures out to a whole year. Now that there are many thousands more applications on the store, I don't think we're ever going to get back to those early days.

I think it's certainly possible to have a big "hit" application that breaks the top 50 and stays there for a while, generating significant income, but I don't think the store is geared towards more substantial applications that will be updated over a long time. Our sales are still non-zero however, so perhaps the level of the tail is just lower than expected.

Also, to be honest, this isn't happening in a vacuum - the state of the global economy isn't really helping matters. A lot of the software on the store isn't essential - PCalc excluded of course - so people might think twice before purchasing if they are worried about their savings. How much of that is a factor, I don't know, but I can't imagine it helps sales.

Since Apple and the App Store is the only way for developers to make their Apps available, does this shift some of the promotional responsibility to Apple? I.e., does Apple have some duty to promote Apps and provide as much visibility as possible, or do iPhone developers, like traditional devs, have to take on the marketing aspect for themselves?

I think Apple does bear some responsibility, at least in so far as making the store as easy to use as possible and helping customers find what they want. And more importantly, highlighting the best examples the store has to offer. If thousands of people are buying something, but it has a lot of one star reviews, why should that be more "popular" in the listings than something that has all five star reviews, but only a handful of people have found it?

I'd like it if a new iPhone user was looking for a more advanced calculator, they could quickly see that PCalc has 70-odd five star reviews and a very loyal group of customers. How you would represent that on the phone, I don't know. But Apple has lots of very talented user interface designers who could come up with something

Of course developers need to do some marketing themselves. But Apple gets 30% of the sales, so I don't think they are completely off the hook.

PCalc is a $9.99 App, which many have said seems to be the "sweet spot" for paid apps at the moment. However, we see some vendors switching from paid to free and back, or running short-term "sales" to either benefit from volume pricing or drive up their popularity before switching back. Is this a reality in the current App Store model, and is it something developers now all have to consider, both for their Apps and competing apps?

That's a really good question, I don't honestly know. Of course, you'll always get people who say that if your software was just that little bit cheaper, they'd buy it on the spot. How accurate that is, I'm not sure. If PCalc was $4.99, would I sell more than twice as many copies? If it was 99c, would I sell more than ten times?

It's a little tempting to just try it, and get some empirical data, but if you reduce the price and find that it doesn't actually help sales that much long term, then you're just losing out. And if the market tends towards lower and lower pricing, then I think the quality of software on the store will suffer.

I priced PCalc at what I thought was a fair price for what I've made, I can't really do much more than that. As it was there on day one, we didn't know what the prices of our competitors were going to be, so we tried not to worry about it too much. As it is, there are calculators on the store from free up to twice the price.

I do think it's equally hard for customers to know whether something that's priced at $9.99 is ten times better than something that's 99c...

What steps could Apple take, short term or long term, to help developers gain greater visibility in the App Store?

Short term, I'd add more categories, perhaps add another level below each of the main categories. Put all the calculators in one place so you only need to look at 20 things in a given section, rather than 2000. Perhaps some filtering options, so you don't see apps with lots of very low ratings. Even just a sorting option to sort by rating would help.

Long term, I think there needs to be a way of presenting what the "best" apps are on the store rather than just those that sell the most copies. I want to see apps ranked by quality, perhaps some combination of sales and rating, maybe with an editorial component. I don't think Apple has the time to do that right now, given that an app still takes a week or so to show up on the store after submission, but I hope they are thinking about it.

Some way to support limited trial versions in the store would also be very useful for customers. The Xbox Live Arcade store on the Xbox 360 has the right model for this - everything on it is a demo version that can be converted to a full version within the app itself.

The iTunes model for music doesn't work as well for selling software.

Last question: does "backspace" belong on a virtualized Calculator? (That's a cheap shot at Apple channeling my counterpart at Crackberry.com... )

Wow, I never even noticed that the Apple calculator doesn't have one. Yes, it certainly does

James, thanks for your time and generosity in sharing your insights with us and our readers!

Dragthings.com is James Thomson's website and blog, and his highly-regarded calculator application for the iPhone and iPod Touch, PCalc is available from the iTunes App Store.