Old-school dubstep generally refers to any dubstep that was made before 2010. The old-school sound is different from modern-day dubstep. An example of old school dubstep would be Burial - Unite.
The sound was characterized by low, deep basslines. It drew heavy influence from dub, which is a subgenre of reggae that originated in the '60s, but it was also highly influenced by '90s and early 2000s UK styles of dance music such as 2-step garage. As with dub, playing the music on good audio equipment is critical to enjoying the music fully because of all of the low frequencies.
Person 1: Is old-school dubstep still being made?
Person 2: Old-school is kind of a historical term, but if you're looking for something dubwise, check out the Deep Medi label.