Will the new Apple Watch even be called the Watch Series 5?

As Apple's big 10 September launch event draws closer, it looks increasingly likely that this year's Watch will be a smaller upgrade than fans have become used to.

Two years ago saw the launch of the Series 3, the first Apple Watch with LTE connectivity, then a year later Apple pulled out all the stops with the Watch Series 4. That wearable included a new ECG app, fall detection, and even a pair of new screen sizes.

But for 2019 and 2020, it is starting to look like the new Apple Watch will be a minor update on the Series 4.

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So far, we have heard that the 2019 Apple Watch will get a pair of new case materials - titanium and ceramic - and it will run the new watchOS 6 operating system.

We know there will at least be some changes, as Apple recently filed a set of four new Watch model numbers to the Eurasian Economic Commission (EEC). But these might just refer to 40mm and 44mm versions of the new premium models with the aforementioned titanium and ceramic cases.

The ever-reliable Apple analyst Ming-Chi Kuo referred to the Watch Series 5 in his recent note to investors, but all he said was that this year's Watch will continue to use OLED screens made by Japan Display. Kuo believes a bigger update, and a switched to MicroLED display technology, will come in 2020.

This all leaves us wondering exactly what will be new for 2019, and whether Apple will even call its latest wearable the Watch Series 5. We might be looking at a second year with the Watch Series 4, or perhaps a 'Watch Series 4S' to take up the slack until a larger upgrade arrives with the Series 5 proper in 2020.

As for any major advancements in health tracking, there has been talk of the Watch Series 5 getting blood pressure monitoring and glucose tracking. But these would likely require certification in each region the Watch is sold is, as was the case with last year's ECG app, before the features can be used.

This approval process prevented the ECG app from working for months after launch in the UK and elsewhere, causing frustration among Watch Series 4 buyers. We're not so sure if Apple will take a similar route so soon with any new Series 5-exclusive features.

We know that the new Watch (along with the Series 1, 2, 3 and 4) will run Apple's new watchOS 6 software. This includes a range of news digital faces, features and apps, but headline-grabbing upgrades like an always-on display and sleep tracking will remain missing from Apple's wearable for another year.

We can offer a glimmer of hope, however, as Apple has begun selling out of some Watch straps in its online store. This would suggest replacements - perhaps even upgrades - are on their way.

Apple Watch fans shouldn't give up hope just yet though. Apple is notoriously good at keeping new products a secret until revealing them on stage - and with the big event taking place on 10 September, we haven't long to wait.