Quote from: Charles-Tim on Today at 01:00:49 PM

Electrum has supported RBF some years ago, but if RBF is enabled, you will need to still flag the transaction to support RBF, unlike now which is dafault while sending unless you flagged the transaction not to support RBF.

It has been enabled by default for years and transactions are sent with the RBF flag. I don't think there were any changes to this behavior recently, 4.x.x but it was changed in 3.3.0, from the changelog.

Quote from: Charles-Tim on Today at 01:00:49 PM

I tried my best to reduce the post contents, but will result to missing of important information for newbies. Just trying to simplify it as it could be.

Newbies don't have to know the technical stuff behind RBF or CPFP, or anything to that extent. They just need to know how to remedy something like this, which the links in the first reply has covered together with pictorial illustrations.