Lumi is currently not HD but we are working hard to make it HD in the next App version. Static (non-HD) wallets stick to using a single address for all transactions. While that's simpler, address reuse undermines your privacy.
HD (or "hierarchical deterministic") wallets generate a new address every time funds are sent to the current address. All addresses generated from the same wallet can be used to receive funds, and all funds sent to any of these addresses will show up in your balance. The balance you see on your main wallet screens represent the total sum between those addresses. .
To send BTC you can either directly open the QR code scanner or tap “Send” and paste an address where you would like to send your bitcoins. Pay a lot of attention to the correctness of the receiving address and never type it manually due to the high risk of making a mistake! Always double-check the address you are going to send bitcoins to because in case you send BTC to the wrong address you will not be able to cancel the transaction or request a refund.
Then you click “Next”. You will arrive at the screen where you can specify the amount you would like to send. You can type the amount either in BTC or in USD (it will calculate the amount in BTC based on the current BTC/USD exchange rate).
The transaction fee is calculated automatically or you can customize it manually. We suggest that you select the recommended fee amount, as it is balanced by speed and cost.
At the first launch of the Lumi application you will be obliged to set a PIN code. We do so in order to protect your funds. We do not require any other registration, and the PIN code is the only way to protect your wallet from any unwelcome quests.
If you would like to change your PIN code you need to go to the sidebar and select “Change PIN”. Then you enter your current PIN and after the new PIN twice.
Go to the sidebar Backup wallet. You will see 12 words one by one. Write a copy of each of these words carefully. Then you will be required to retype all 12 words in order to check the correctness of your backup. Store your copy of these 12 words (mnemonic) in a very safe and secure place and never give it to anyone you don’t want to have access to your funds.
Never switch your wallet without having a Backup. The only way to get access to your funds is with your 12 word Backup Phrase.
We ask that you write down your 12-word Backup Phrase in the exact sequence before you exit your wallet as your funds and private key are tied to your unique Backup Phrase. Your 12-word Backup Phrase allows you to restore your wallet and regain access to your funds at any time on any device that supports Lumi wallet. After switching the wallet, you will not have any other way to access your funds except the 12-word backup phrase.
In the unlikely event that Lumi, as a company, is no longer around, you may also use your 12-word phrase to transfer your existing funds in Lumi to a similar wallet service that utilizes the mnemonic system.