I have Chrome extension which store user data in local storage. Now I'm developing an update I have to migrate user data to new version when they update to new version.

When I try this

chrome.storage.local.get([old save name], result => {
   console.log(JSON.stringify(result))
})

it's empty.

What is the issue? I try the new version on developer mode I guess the new version is acting like totally different extension, maybe when I publish it will works well.