I sent a transfer of an ERC20 token from my wallet to an exchange wallet with the lowest gas (5 Gwei). It's now been 1 day 6hrs and still shows as pending. Is there a way I can upgrade or cancel this pending low gas transaction? Thank you!
Just to supplement @Thiago's valid answer.
Transactions can't be directly cancelled or upgraded. The only thing you can do is send a new transaction with the same nonce but with higher gas price. If your new transaction get mined first (as it probably will as it has higher gas price) then the old transaction becomes obsolete as it has the same nonce.
Depending on your client you may not be able to set the nonce manually. If that's the case your only option is to use another client which allows you to modify the nonce manually.
Or you can always just keep on waiting and it will get mined eventually when the network is less congested. It might take a day or a year...