I went from dot net 1.1 to vs2017 with the following steps:
copy the dot net 1.1 project folder to a new folder
delete the licenses.licx file
open that copied project in vs2017 and finish the upgrade wizard
change the target dot net framework to a newer version
remove the references to the dot net 1.1 syncfusion assemblies
add in the references to the new syncfusion assemblies
save & exit
delete the "backup" folder that vs2017 creates under the copied folder
run the syncfusion control panel, select utilities/project migration, point to the copied folder, select the correct dot net framework version from the drop-down, select 'remove hint paths'