Rn-fetch-blob: RNFetchBlob.fs.mkdir fails after update targetSdkVersion 28 to 29 in Samsung Galaxy M31

[wtRahul]

A few days earlier I got a mail from the play store that I need to change my targetSdkVersion 28 to 29 before 2 November 2020. When I changed this RNFetchBlob.fs.mkdir failed in Samsung Galaxy M31. If I run in another device it works good.
Please guide me on what breaks the code.

"rn-fetch-blob": "^0.12.0",
"react-native": "0.61.5",
"react": "16.9.0",

[AGIsmail]

Where are you trying to mkdir?
Perhaps you need to opt out of scoped storage
https://developer.android.com/training/data-storage/use-cases#opt-out-scoped-storage

[wtRahul]

Here some steps for this issue.

1. Change build version
   buildToolsVersion = '29.0.2'
   minSdkVersion = 21
   compileSdkVersion = 29
   targetSdkVersion = 29
   in android/build.gradle

2. and than put

android:requestLegacyExternalStorage="true"
..........

in your AndroidManifest.xml file

1. rebuild your project

Everything starts working perfectly.