Pursuant to new App Store Guidelines Apple removed 1
Vaping is often produced by the vape industry as healthier and safer than smoking cigarettes but the government and private organizations have advocated the use of vape products almost as passionately as they do with smoking, and for good reason. The CDC reports that vaping has resulted in at least 2,172 cases of respiratory illness / injury (including internal burns), and at least 42 deaths were recently caused by nicotine weapon products. It's certainly not as high as smoking-related deaths and illnesses, but these numbers will only grow as more research is done and vaping's popularity increases.
Many companies have responded to these figures by removing or prohibiting the sale or advertising vape-related products, consequently Apple's decision to withdraw all vaping apps from the App Store. While all the apps in one case were all of a sudden, it wasn't exactly surprising; Apple stopped accepting submissions for vape-related apps as early as June, and this formal ban is the final step in implementing its anti-vape policy.
If you, like me, weren't aware that vaping apps were even a thing in the first place then this probably doesn't mean much to you, but those who relied on an iOS app to control or Monitor their vaping devices must find a new platform. Both Google Play and Amazon App still have plenty of vape apps listed – some of which were also available in the Apple App Store – but these are Android app markets and won't work with Apple Products. Currently, if you don't want to jailbreak an iOS device so you can run apps that aren't the App Store, your choices are to jump to Android or, change your vape or, you know, quit vaping.