Minecraft – Hosting the own server for Minecraft pocket edition

For the textures, you can easily change it by changing the terrain.png file with your desired texture pack. But beware that PC's terrain.png may vary with PE's. Try searching for a similar or exact texture on the Minecraft Forums. They have lots of ported texture pack.

For maps, you will need to first port it because MCPE maps aren't infinite and a portion of the world will need to be cut, pasted and then saved in MCPE format. Then you can transfer it to your Android device.

Note: My previous answer was for iOS devices. I have changed my answer to fit the question and hope it helps.

The only way to do that would be to both: have your device rooted (jailbroke) and possess a copy of the outdated version.

I would check around and see if there is a modder community based around pocket edition. If you do have a rooted device. They would be the place to have a chance at that file.