Every once in a while, when you visit Polkadot-JS UI, you may see a counter next to Settings or this warning asking you to apply updates to your extension:

This means there was a runtime upgrade since you last used Polkadot-JS UI, and your extension needs to catch up with the latest metadata. Metadata includes essential information that allows you to verify what you are signing, like descriptions for each extrinsic.

‼️ IMPORTANT

The Polkadot extension is an account manager meant for power users and developers. There are several user-friendly browser extensions funded by the Polkadot Treasury that support a lot of features right from the extension. Discover them on Polkadot's homepage.

In this guide, we will use the Polkadot browser extension, but the same steps can be used for any other extension within the Polkadot ecosystem.

⛔ READ THIS FIRST! 

Only allow metadata updates from trusted sources, like Polkadot-JS UI. Do not sign a transaction if you cannot verify what you are signing or you suspect you might be signing a different extrinsic than the one intended.

How to update the extension metadata on Polkadot-JS UI

1. If one of your extensions needs to be updated, you will see a counter next to Settings and a warning on the Accounts page on Polkadot-JS UI:

2. Please navigate to Settings and switch to the Metadata tab, or simply click the link in the message :

Here, you will see what extensions can be updated. Click the "Update metadata" button to apply updates.

3. An extension window will pop up:

Here, you can see:

• From: the source of the metadata. Remember only to accept updates from trusted sources.
• Chain: each chain has its own metadata, so you must update it separately for each network you use.
• Decimals and Symbol: this explains how many Planck one coin native to the chain contains and what the coin symbol is.
• Upgrade: the runtime version you used until now and the version you are about to use.

4. Complete the process by clicking "Yes, do this metadata update".