Question about targetSdkVersion

I’m facing a problem with the comprehension of the targetSdkVersion.

Let’s say i have created a application with a targetSdkVersion 23.
Then, later i change it and build it for targetSdkVersion 24.
Is this mean that all the plugins i used before in the 23 must be upgraded too ?

Before, my application was running well with the katzer/cordova-plugin-email-composer plugin which was runing on the targetSdkVersion 23.

Now, i decide to update it for targetSdkVersion 24 (to support all phone with new OS)

Than, i face this next issue, what should i do:

“GMail 5.0 added some security checks to attachments it receives from an Intent. These are unrelated to unix permissions, so the fact that the file is readable doesn’t matter.”