Update master workbook data from separate workbooks

I'm after ideas as to the best way to have the existing data in a master workbook updated according to changs made on two separate workbooks.

I'm not sure the best way to go about this...

- I've thought of a straight copy/ paste however, i can't rely on those making the changes to not erroneously delete needed information, which could create issues down the line.

- There's 1700 rows and 20 columns of data, of which any may be updated, so i'd imagine searching/ looping/ updating row by row would be very time consuming
.
I've attached two workbooks
1. Master - which will get updated via the macro.
2. Backlog - this is the workbook that people will be updating

If someone could point me in the right direction, i could figure the code out