The phrase "direct successor" refers to the person or thing that comes immediately after another person or thing in a specific order or position. Full definition
The Tasmanian Government replied that it supported the view of eminent Australian historian Professor Henry Reynolds that preceding Tasmanian governments were direct successors of the colonial governors of the 1830s and, as such, the current Tasmanian Government has a responsibility to rectify past injustices. (humanrights.gov.au)
Two of the iPhones Apple is planning to launch in 2018 will be positioned as direct successors to the iPhone X, one with a standard 5.8 - inch display like the current iPhone X and one in a larger «Plus» size with a 6.5 - inch display. (macrumors.com)
The smaller Pixel 2 is understood to be a more direct successor to the 2016 devices and will feature an almost identical look with regularly sized bezels, as well as a 16:9 screen. (androidheadlines.com)