diff --git a/.travis.yml b/.travis.yml
index 26c9eb9..44c5365 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,6 @@
 language: csharp
 mono: none
-dotnet: 2.1.502
+dotnet: 3.0.100
 script:
   - cd maildisk
   - dotnet publish -r win-x86
@@ -11,7 +11,7 @@ script:
   - dotnet publish -r linux-arm
   - dotnet publish -r linux-arm64
   - dotnet publish -r osx-x64
-  - cd maildisk/bin/Debug/netcoreapp2.1/
+  - cd maildisk/bin/Debug/netcoreapp3.0/
   - tar -zcvf ../../../../../linux-x64.tar.gz linux-x64/publish/
   - tar -zcvf ../../../../../linux-arm.tar.gz linux-arm/publish/
   - tar -zcvf ../../../../../linux-arm64.tar.gz linux-arm64/publish/
diff --git a/maildisk/maildisk/maildisk.csproj b/maildisk/maildisk/maildisk.csproj
index bb53bb0..dfcd874 100644
--- a/maildisk/maildisk/maildisk.csproj
+++ b/maildisk/maildisk/maildisk.csproj
@@ -2,10 +2,12 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp2.1</TargetFramework>
+    <TargetFramework>netcoreapp3.0</TargetFramework>
     <Authors>chenxu</Authors>
     <Company>chenxublog.com</Company>
     <Description>make your e-mail become a netdisk!</Description>
+    <PublishTrimmed>true</PublishTrimmed>
+    <PublishSingleFile>true</PublishSingleFile>
   </PropertyGroup>
 
   <ItemGroup>