Samsung is intended to strengthen its fusion with Andoid, according to the Google co-designed Wear OS 3. Having been in the wearable market for years, the company is still being complained about its limited third-party apps, despite a fantastic base experience. The cooperation with Google this time will make it more convenient to connect Galaxy watches with Galaxy phones and other Android-supported handsets.

On the other side, Galaxy Watch 4 for the first time offers no support for iOS, if you chech the spes of the watch on the company’s website. This means that you can’t connect Galaxy Watch 4 with your iPhone or any other Apple devices. The move will undoubtedly discourage some potential buyers, but anyway, it’s a trend that more and more non-iOS smartwatches choose to stop compatibility with Apple.
The good news is that your older Galaxy smartwatches won’t be affected by this policy, you can still connect Galaxy Watch 3, Galaxy Watch Active 2 and the like to any Apple devices.

As for Android smartphones, Samsung says that there also no support for Android 5.0, while Android 6.0 is the minimum threshold. In addition, you need to make sure Play Services and Play Store are on your phone before enabling the device to work. As below is the Samsung details:
Compatible with Android 6.0 or higher, RAM 1.5GB above.
Device activation is only available after connecting to a smartphone that supports Google Mobile Services(GMS). Please refer to your device manufacturer to find out whether your smartphone supports Google Mobile Services(GMS). Compatible smartphones and available features may vary by region, carrier and device.
Samsung Galaxy Watch 4 and Watch 4 Classic are currently available for pre-order and will go on sale on August 27th. Or you’re seeking for alternatives? Why not have a check Apple Watch Series 6, Samsung Galaxy Watch 3, and Fitbit Versa 3.