In terms of features there isn't a lot to talk about either. The M40 is a very simple camera designed for point-and-shoot snapshots, so you wouldn't expect it to be overloaded with complicated stuff. It has a standard Pentax compact camera menu that has barely changed in the past four or five years, but at least it does offer wide area, spot or tracking AF, ISO settings from 50-3200, and adjustable contrast, saturation and sharpness. The portrait mode does have face detection technology, however the menu offers none of the common light metering options such as centre-weighted or spot metering, relying on only TTL multi-segment metering and exposure compensation to get you through any difficult exposures. It does have a wider than average range of focusing options, including macro, super-macro, infinity, pan-focus and even manual focusing. Unsurprisingly it also lacks any sort of mechanical shake reduction, instead it has "Digital SR", in other words it increases the ISO setting to produce a faster shutter speed, at the cost of increased image noise. The M40 has the same playback mode features as the M30, including cropping and resizing, rotation, digital filters, red-eye reduction and the ever-popular frame composite mode.
The built-in flash is also the same as the M30, and it's a very good one, however I noticed that on the box, one of the selling points listed for the M40 is a massive 15.5 metre flash range, which would be comparable with the most powerful professional flashguns designed for SLRs. I'm afraid this is a bit of a cheat though. It is traditional to specify flash ranges at fixed ISO settings, usually 100 ISO. Under these conditions most compact cameras have a flash range of around four metres at wide angle, which is perfectly adequate for most social photography. The M40's flash only has that huge range at the maximum sensitivity setting of 3200 ISO in Digital SR mode, and with the best will in the world, picture quality at that setting is pretty terrible. In normal Auto ISO mode the camera selects 800 ISO for flash shots, giving a range of eight metres, but still rather poor image quality. At the more normal 100 ISO the flash range is actually about five metres which is still fairly respectable, and the frame coverage is excellent, so why try to bolster this performance with spurious claims?
Another feature that is unchanged from the M30 is the autofocus system, and reading my review of it now it strikes me that I sounded perhaps a bit harsh. Although it is slow, it will focus in quite dim light, having no trouble in a large room lit with a 60W bulb, and only a little trouble with just a reading lamp. However it still has no AF assist lamp, so it can't focus in the dark, possibly something of a handicap in a camera designed for social photography.