Current active window snapping window to top or bottom half of the screen with Windows+Shift+Up/Down working with API v.1.1 of AutoKey (but works with Autokey latest version from its download). From upstream https://superuser.com/a/1856438/466443

WindowSnapping.ahk

; ----------
; Move window up (Windows + Shift + UP)
+#Up::

target_monitor := 2

SysGet, MonitorCount, MonitorCount

; get current active window
WinGetPos, curr_win_x, curr_win_y, curr_win_width, curr_win_height, A

; loop to check which screen the current active window shall be within
Loop, %MonitorCount%
{
	SysGet, Monitor, Monitor, %A_Index%

	; care only the top-left position of the window
	if (curr_win_x >= MonitorLeft && curr_win_x < MonitorRight && curr_win_y >= MonitorTop && curr_win_y < MonitorBottom)
	{
		target_monitor := A_Index
		;MsgBox, Detect active window is at monitor %A_Index%
		;MsgBox, %MonitorLeft%, %MonitorRight%, %MonitorTop%, %MonitorBottom%
		break
	}
}


; bound check the target_monitor
if (target_monitor < 1 && target_monitor > MonitorCount)
{
	MsgBox, %target_monitor% is out of bound of %MonitorCount%
	return
}

SysGet, Monitor, Monitor, %target_monitor%
WinMove, A,, MonitorLeft, MonitorTop, (MonitorRight-MonitorLeft), (MonitorBottom-MonitorTop)/2.0
return

; ----------
; Move window down (Windows + Shift + DOWN)
+#Down::
target_monitor := 2

SysGet, MonitorCount, MonitorCount

; get current active window
WinGetPos, curr_win_x, curr_win_y, curr_win_width, curr_win_height, A

; loop to check which screen the current active window shall be within
Loop, %MonitorCount%
{
	SysGet, Monitor, Monitor, %A_Index%

	; care only the top-left position of the window
	if (curr_win_x >= MonitorLeft && curr_win_x < MonitorRight && curr_win_y >= MonitorTop && curr_win_y < MonitorBottom)
	{
		target_monitor := A_Index
		;MsgBox, Detect active window is at monitor %A_Index%
		;MsgBox, %MonitorLeft%, %MonitorRight%, %MonitorTop%, %MonitorBottom%
		break
	}
}


; bound check the target_monitor
if (target_monitor < 1 && target_monitor > MonitorCount)
{
	MsgBox, %target_monitor% is out of bound of %MonitorCount%
	return
}

SysGet, Monitor, Monitor, %target_monitor%
WinMove, A,, MonitorLeft, (MonitorBottom-MonitorTop)/2.0 + MonitorTop, (MonitorRight-MonitorLeft), (MonitorBottom-MonitorTop)/2.0
return