When I tried to restore this wallet using the Electrum Android app there is no way to enter capital letters, only lowercase. Does this mean my custom seed will only work on the Windows version?
For the purpose of this thread, I made a wallet today using an uppercase extended word on Electrum PC and imported it to Electrum Mobile to see if typing a lowercase extended word would display the same wallet.
After I confirmed all address from the Electrum PC and Electrum mobile are the same. So the extra word even you type it in lowercase or uppercase, the wallet should be the same as what you created from Electrum PC.