From D-Like’s Facebook official post:
What’s updated on Re-R HYBRID 2017 (DL500)
Hi guys. We have got some questions about the latest version of Re-R HYBRID. Mostly, what’s the difference from the old model. The 2017 model was reviewed the whole process of production and studied again the machining precision. The basic components and structure were kept as original. However, Yoshi spent a much time for this updates with passion, he has poured his energy as almost same as developing brand new product.
Even the basic components were not changed, there are some significant updates for the 2017 model. The followings were picked up from Yoshi’s blog post.

#1 Main Shaft Mount (NEW)

To improve the accuracy of the spool gear rotation, more responsive acceleration and to endure the higher powered tuning, the main shaft mount was added on the front bulkhead.

Main Shaft Mount

#2 Center Drive Shaft Protector (NEW)

The center drive shaft protector covers is put on the motor-side end of the drive shaft to protect the ball shape head. The abrasion of the ball head causes a micro vibration and obstructs the responsive acceleration work.

Center Drive Shaft Protector

#3 Center Drive Cup and E-Clip

Increasing the thickness of center drive cup and e-clip makes it withstand the high RPM.

Center Drive Cup and E-Clip

#4 M4 x 3mm Set Screw

Old) M3 x 3mm -> New) M4 x 3mm To fix more stronger the spur gear and main shaft.

M4 x 3mm Set Screw

#5 Rear Lower Arms

Some more dumper fixing hole on the rear lower arms.