How long will this Bitcoin rally continue?

Ether and bitcoin rallied for a fourth day on Tuesday to record highs off the back of a weaker dollar, an upcoming upgrade and positive investor sentiment.

Ether was up 1.6% in 24 hours, having risen earlier to hit a high of $4,842.54 on Coinbase, while bitcoin was last up 3% after reaching a new peak of almost $68,600. Ether has climbed 9% over the last four days, while bitcoin has risen about 8%.