#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "^(?![\s\S]*<othermeta content="V7" name="version"\/>)[\s\S]*<othermeta content="V6" name="version"\/>\K"
Local $sString = "<othermeta content="V5.1" name="version"/>" & @CRLF & _
"<othermeta content="V5.2" name="version"/>" & @CRLF & _
"<othermeta content="V6" name="version"/>" & @CRLF & _
""
Local $sSubst = "\n<othermeta content="V7" name="version"/>"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm