I have upgraded whatsapp on my phone but i dont like the new emojis on whatsapp so the quesition is : Is this possible to get my old emojis back using whatsapp's latest version apk with apktool debugging?
You can try downgrading your WhatsApp version, by downloading an older APK.
before you download the apk make sure to uninstall WhatsApp.
After that, download the desired apk from here
You should then be able to go thru the regular registration process in WhatsApp.
To make sure it doesn't automatically update the app, go to the play store, search for 'WhatsApp' in the search bar, press on the WhatsApp icon, then press on the three dots menu on the top right of the screen and deselect 'auto update'
Note: WhatsApp might give you an error telling you to download the latest version. Also note: just because you will now have the older version of emojis, doesn't mean that the recipient will see them in that way. The opposite is also true, if someone sends you an emoji that came with the latest update, chances are, that you will not be able to view them.
I'm not responsible if anything goes wrong.
What you want is not possible. You want the latest version of the app, but the old emojis. That is impossible for anyone but the developer.
When an app is built, all its components are consolidated into one project. It is not possible for the layman to change any one component of the project. The previous emojis were in one project, while the modified emojis are in another project. You cannot just change the emojis and keep the rest at the latest version.
If you are okay with downgrading, then you can try what @Abochur has said, or simply uninstall the updates. Otherwise you'll have to get used to the new emojis.