3325086 - BTP application failed with "internal server error"

BTP application failed with error "internal server error".

From approuter log, error message as below:

*******

GET request to <xxx>

completed with status 500 - xs-app.json/routes/2: Format validation failed (Route has cacheControl with no localDir)"}

*******

The project is using standalone approuter, and from project package.json, @sap/approuter version is quite old, such as 6.x.x or even older.

              "engines": {

                             "node":"^12.0.0 || ^14.0.0"

              },

              "dependencies": {

                             "@sap/approuter": "6.x.x"

SAP Business Technology Platform

node, engines, approuter, app router, @sap/approuter, Route has cacheControl with no localDir, xs-app.json/routes/2: Format validation failed , KBA , BC-XS-APR , XSA Application Router , Problem