.net core - Error on netcoreapp1.1 when adding a netstandard1.6.1 reference -

i tried update website project netcoreapp1.0 netcoreapp1.1 , dal project (netstandard1.6.1) error pops when try add dal project reference website project.

heres project.json of projects:

dal project(netstandard1.6.1)

{   "version": "1.0.0-*",   "dependencies": {     "microsoft.aspnetcore.identity.entityframeworkcore": "1.1.0",     "microsoft.entityframeworkcore.sqlserver": "1.1.0"   },   "frameworks": {     "netstandard1.6": {       "imports": "dnxcore50",       "dependencies": {         "netstandard.library": "1.6"       }     }   } } 

website project(netcoreapp1.1)

{   "dependencies": {     "bundlerminifier.core": "2.2.301",     "microsoft.aspnetcore.authentication.cookies": "1.1.0",     "microsoft.aspnetcore.diagnostics": "1.1.0",     "microsoft.aspnetcore.diagnostics.entityframeworkcore": "1.1.0",     "microsoft.aspnetcore.identity.entityframeworkcore": "1.1.0",     "microsoft.aspnetcore.mvc": "1.1.0",     "microsoft.aspnetcore.razor.tools": {       "version": "1.0.0-preview2-final",       "type": "build"     },     "microsoft.aspnetcore.routing": "1.1.0",     "microsoft.aspnetcore.server.iisintegration": "1.1.0",     "microsoft.aspnetcore.server.kestrel": "1.1.0",     "microsoft.aspnetcore.staticfiles": "1.1.0",     "microsoft.entityframeworkcore.sqlserver": "1.1.0",     "microsoft.entityframeworkcore.sqlserver.design": "1.1.0",     "microsoft.entityframeworkcore.tools": {       "version": "1.0.0-preview2-final",       "type": "build"     },     "microsoft.extensions.configuration.environmentvariables": "1.1.0",     "microsoft.extensions.configuration.json": "1.1.0",     "microsoft.extensions.configuration.usersecrets": "1.1.0",     "microsoft.extensions.logging": "1.1.0",     "microsoft.extensions.logging.console": "1.1.0",     "microsoft.extensions.logging.debug": "1.1.0",     "microsoft.extensions.options.configurationextensions": "1.1.0",     "microsoft.visualstudio.web.browserlink.loader": "14.1.0",     "microsoft.visualstudio.web.codegeneration.tools": {       "version": "1.0.0-preview2-final",       "type": "build"     },     "microsoft.visualstudio.web.codegenerators.mvc": {       "version": "1.0.0-preview2-final",       "type": "build"     }   },    "tools": {     "microsoft.aspnetcore.razor.tools": "1.0.0-preview2-final",     "microsoft.aspnetcore.server.iisintegration.tools": "1.0.0-preview2-final",     "microsoft.entityframeworkcore.tools": "1.0.0-preview2-final",     "microsoft.extensions.secretmanager.tools": "1.0.0-preview2-final",     "microsoft.visualstudio.web.codegeneration.tools": {       "version": "1.0.0-preview2-final",       "imports": [         "portable-net45+win8"       ]     }   },    "frameworks": {     "netcoreapp1.1": {       "dependencies": {         "microsoft.netcore.app": {           "type": "platform",           "version": "1.1.0"         }       },       "imports": [         "dotnet5.6",         "portable-net45+win8"       ]     }   },    "buildoptions": {     "emitentrypoint": true,     "preservecompilationcontext": true   },    "runtimeoptions": {     "configproperties": {       "system.gc.server": true     }   },    "publishoptions": {     "include": [       "wwwroot",       "**/*.cshtml",       "appsettings.json",       "web.config"     ]   }, } 

in dal project.json, version of netstandard.library must 1.6.1 this:

"frameworks": {     "netstandard1.6": {       "imports": "dnxcore50",       "dependencies": {         "netstandard.library": "1.6.1"      }    } }