The dialogue seems to be taken from the revised dialogue of the Super NES remake. Most likely the changes are only for the more important scenes and aren't all that frequent. But in any case, it wouldn't be too hard to modify the mobile version's translation to better match the famicom version's dialogue, and even make it less wordy. If not, then I would have to recommend the Game Boy version's translation since it seems to be far better written than both the NES translation and the fan-translation that was linked to.
Below is a comparison of Erdrick/Loto's message to his descendant. However, I modified the mobile version's translation in two ways: removed the last two lines which was added by the Super NES version, and made it slightly less wordy.
NES: "I am Erdrick and thou art my descendant. Three items were needed to reach the Isle of Dragons, which is south of Brecconary. I gathered these items, reached the island, and there defeated a creature of great evil. Now I have entrusted the three items to three worthy keepers. Their descendants will protect the items until thy quest leads thee to seek them out. When a new evil arises, find the three items, then fight!"
GB: "My name is Loto. To my descendant... To reach the demonic island that can be seen from Tantegel, three magic implements were needed. I used them to cross the sea and defeat the lord of the demons. I will entrust the three mystic items with three sages. Their descendants will guard them. When evil returns to that island, collect the items and fight it. The three sages are waiting. It is your duty to go, my progeny!
Mobile: "I am Erdrick. Here me well, descendant... If you would reach the evil island visible from Tantegel's Shore, you will require the three sacred artefacts. Gather them, and you may yet cross to that accursed isle, and destroy the source of all evil, as I , too, did so long ago. Before my passing, I entrusted the three objects to three great sages. If the fates have been kind, their descendants guard them still. When evil rules the ill-starred isle once more... Gather the hallowed triad, and strike a blow for the cause of light."