The odd one out

Normal sudoku rules apply. Place the digits 1-9 once each in every row, column and 3x3 box. Clues outside the grid with an arrow are little killer clues of which sum the digits along the indicated diagonal, digits may repeat (if other rules allow). Clues outside the grid without an arrow are numbered rooms clues of which indicate the digit which has to be placed in the Nth cell in the corresponding direction, where N is the digit placed in the first cell in that direction. Adjacent digits along a green line must differ by at least 5. Note.. one of the whisper lines is also a palindrome and up to the solver to determine which. Digits in a dotted cage without repeat sum to the total given in the top left corner of the cage. Cells separated by a black dot has one digit double the other (1:2 ratio). Digits along a grey line must read the same forwards as backwards. Which clue is the odd one out? There is a hidden word.