When Apple announced the Apple Watch Series 8 connected Wednesday, it introduced a caller debased powerfulness mode diagnostic that lets the wearable treble its artillery beingness by turning disconnected a fewer features. It won’t beryllium constricted to Apple’s latest devices, though — during the presentation, Apple said debased powerfulness mode is coming to “the Series 4 and later” with watchOS 9, which is launching September 12th.

The institution didn’t accidental whether the mode would beryllium arsenic effectual connected older devices arsenic it claims it volition beryllium connected the Series 8 and Apple Watch Ultra (Apple says its bigger ticker volition beryllium capable to spell from 36 hours of runtime to 60 with the mode turned on). But based connected what we cognize astir however it works, it’s wide that it’ll beryllium little effectual connected astatine slightest a fewer models.

Low powerfulness mode conserves foodstuff by turning disconnected immoderate features similar the always-on display, workout autostart, bosom wellness notifications, and more, portion keeping things similar enactment tracking and autumn detection switched on. While turning the surface afloat disconnected volition perfectly amended artillery beingness connected immoderate of Apple’s watches, it won’t bash overmuch for the Series 4, oregon either exemplary of the SE — they don’t person always-on displays to statesman with.

Apple didn’t respond to The Verge’s petition for remark connected what types of features it’ll crook disconnected connected watches similar the caller SE, oregon whether the diagnostic is coming to the fund exemplary astatine all. The SE does acceptable the statement of “Series 4 and later,” but debased powerfulness mode isn’t mentioned connected the SE’s merchandise page.

Despite the caveats, it’s bully to cognize that there’ll soon beryllium a mode to eke retired astatine slightest a small much runtime connected your older watch, without having to power into the ultra-bare-bones power reserve mode, which lone displays the clip erstwhile you property the watch’s broadside button. That’s particularly existent arsenic these devices and their batteries get older — though it’s worthy noting that Apple volition service ticker batteries for $79 if you truly privation to marque your Series 4 past arsenic agelong arsenic possible.