Please don't change the international boundaries. 
Also check the official  Albanian Gov Geospatial system if you have any doubts. All information that is in the Albanian site is been recorded and documented in detail as well for possible future altercations on this matter. Thank you. Here is another official site registered in the US and documenting the border from Albanian info (	Institutin Topografik të Ushtrisë) since the 1970's along with War Map from the British Government (1943) that shows Gistova as part of Greece. (2) 
1)https://shop.geospatial.com/publication/38PCREFVGPMH4RPD0MSAVZHMV6/Albania-1-to-100000-Scale-Topographic-Maps
2)https://collections.lib.utexas.edu/catalog/utlmaps:1cce30dd-aab6-44d3-8aed-6a389d1afed1

