You are going to get a LOT of contradictory information and advice here asking that question. I can only tell you that most of what is/will be said is tainted by unsubstantiated opinion.
But I will tell you facts. I have had three diesels, two that were supposed to only use no more than 5% biodiesel, and the third no more than 7%. All three have been run at higher concentrations without incident. One of the 5%ers has 180,000 miles, of which around 100,000 miles was more or less continuously at B20 to B50, with occasional brief periods on B100. At around 125,000 miles the injection pump started leaking and had to be replaced. It should be noted that this seems to have happened to others of its type that have never run biodiesel, so I'm not sure it had anything to do with biodiesel.
The second, another 5%er, ran for around 50,000 miles on B20-B50 without incident. At 150,000 miles, an overheating incident while towing caused a blown head gasket and cracked head, which was replaced. At 200,000 miles, the last being with no biodiesel, the rebuilt head with new valves, dropped an exhaust valve killing the engine. Clearly the biodiesel had nothing to do with the dropped valve.
The third, and newest of them now has 110,000 miles, and though officially limited to B7, has seen an occasional tank of up to B20, without skipping a beat. This vehicle is the only one of the three with a DPF.
There are strongly opinionated people who will insist that a single tank of 5% biodiesel is the reason their radio no longer works. I know this, because I've met them.
Frankly, my own personal experimentation has resulted in my own opinion that use of biodiesel has no untoward consequences for engines, enough so that I don't worry about it at all.
