Short answers, pulled from the story.
The transition from Elder Futhark to Younger Futhark began during the 7th and 8th centuries. This period saw a gradual shift in how the Norse people wrote their language before the reduction to sixteen runes was complete by the late eighth century.
The Younger Futhark contains sixteen characters while the earlier Elder Futhark served as an alphabet with twenty-four characters. The change happened alongside phonetic shifts in spoken Old Norse that forced scribes to simplify the alphabet.
The Younger Futhark split into long-branch Danish and short-twig Swedish or Norwegian forms. Long-branch runes appeared on stone monuments throughout Denmark while short-twig versions dominated private messages carved on wood in Sweden and Norway.
More than six hundred inscriptions using medieval runes have been discovered in Bergen since the 1950s. Most are carved onto wooden sticks known as Bryggen inscriptions which prove runes coexisted with Latin alphabets for several centuries.
Dalecarlian runes remained in some use up to the twentieth century within Dalarna province. A mix of runes and Latin letters developed there during the early sixteenth century before contemporary culture adopted symbols like Bluetooth merging hagall and bjarkan initials.