changing the flutter app icon for ios and android devices

[Bened]

FLUTTER  APP ICON FOR IOS DEVICE:

Does it matter if I replace the filename by a simple one as long as it matches the name of the new image and will it works on an ios device?

example:

source code:

    {

      "size" : "76x76",

      "idiom" : "ipad",

      "filename" : "Icon-App-76x76 @2x.png",

      "scale" : "2x"

    },

new code:

    {

      "size" : "76x76",

      "idiom" : "ipad",

      "filename" : "152.png",

      "scale" : "2x"

    },

152.png having a size of 152 * 152. 

Being on Windows, I do not have Xcode

Am I allowed to delete this part of the code:

  "info" : {

    "version" : 1,

    "author" : "xcode"

  }

FLUTTER APP ICON FOR ANDROID DEVICE:

Is that normal I can only generate a  legacy Launcher Icons and not an adaptative one, it is telling me 'Project must be built with SDK 26 or later to use adaptative icons'

I am targeting the last version:

android {
    compileSdkVersion 29

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    lintOptions {
        disable 'InvalidPackage'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.xxxx.flutter_appkkk"
        minSdkVersion 16
        targetSdkVersion 29
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }