Running low on inventory for the older model, Apple has informed its retail staff to substitute some Apple Watch Series 3 repairs with the Series 4 globally, the media reported.The company announced the change in an internal memo that was delivered to Apple Store repair staff and the iPhone maker's Authorized Service Providers around the world, 9To5Mac reported on Monday. As of now, Apple has not provided any details about how long would the Series 3 constraints and Series 4 upgrades scheme last. The new repair and replacement upgrade for the Apple Watch is the latest of several instances of the company substituting Apple Watch repairs with newer models. The iPhone-maker released its Apple Watch Series 3 with cellular connectivity built in 2017. The 38mm variant of the watch currently costs Rs 28,900, while the 42mm GPS variant is priced at Rs 31,900 in India. Launched last October, the price of Apple Watch Series 4 GPS is Rs 40,900 for the 40mm variant and Rs 43,900 for the 44mm version. "As usual, it's not guaranteed that all locations will acknowledge existence of this internal policy, especially given that there is no definitive end date, so your mileage may vary," the report said.In January, the company announced that some first-generation Apple Watches and Apple Watch Series 1 could qualify for Series 2 replacements, due to supply constraints on repair parts for the older models. Earlier this month, Apple confirmed that repairs of certain Apple Watch Series 2 models will be fulfilled with equivalent Series 3 models due to temporary shortages of unspecified Series 2 parts, the report added.