Fortress Sudoku (Mini Sudoku Series #28)

Fortress Sudoku is one of the Sudoku types which I created for Sudoku Mahabharat Episode 6 which is themed Neighbours. This was the backup Sudoku type and in the end, we decided not to include this Sudoku type. 

I have already posted 9x9 Fortress Sudoku which I created for the Sudoku Mahabharat championship. 

I am posting this Fortress Sudoku as 28th Sudoku in Mini Sudoku Series. Can you solve this Fortress Sudoku puzzle?

Rules of Fortress Sudoku

Mini Classic Sudoku Rules apply. Additionally, a digit in a shaded cell must be higher than digits in all orthogonally adjacent white cells.

Fortress Sudoku (Mini Sudoku Series #28)

Fortress Sudoku (Mini Sudoku Series #28) Solution

Previous Mini Sudoku Series Puzzle: Outside Killer Sudoku

Next Mini Sudoku Series Puzzle: Classic Sudoku

Solution of Touchy Sudoku (Daily Sudoku League #94)

Touchy Sudoku (Daily Sudoku League #94) Solution