Blobs in Walrus are designed to be immutable, which means you cannot update a blob without its identifier changing. The blob ID is a hash of the blob's content, so any change in the content would result in a different hash and thus a new ID. In case you need to make updates, you'll have to create a new blob with the updated content, which will generate a new blob ID. The ID essentially serves as a unique identifier for that specific version of the blob content.

For projects like yours, consider designing your application logic to handle versioning or referencing new blob IDs when updates are made. This approach aligns with the immutable nature of Walrus and other similar systems.