Please check the stacking guide for 8070 code I recommend going with 8070f Code, we have two types of images Routing and switching. Not sure what version if it is routed or switched code you are running now and what model of 7150 you have:https://support.ruckuswireless.com/documents/2125
This is the information from the stacking guide:
Planning to build a traditional stack
Before you begin to build a traditional stack, you should be familiar with supported stacking software requirements, topologies,
All units in a traditional stack must be running the same software version.
Maximum configuration file size for any stack is 1 MB.
Traditional stack requirements
Traditional stacks must contain devices of the same type or product line. For example, a traditional stack cannot combine ICX7150, ICX 7250, ICX 7450, ICX 7650, or ICX 7750 devices. However, a traditional stack can contain any combination of devices from the same product line, for example, any combination of ICX 7250 devices.
A core stack for an 802.1br (SPX) configuration is a traditional stack that contains only ICX 7750 devices, although the
stack may contain different types of ICX 7750 devices. Refer to the Ruckus FastIron Campus Fabric Configuration Guide for
Ruckus traditional stacking topologies
Ruckus traditional stacking technology supports linear and ring topologies.
Although Ruckus stackable units may be connected in a simple linear topology, Ruckus recommends a ring topology because it offers the best redundancy and the most resilient operation. Unicast switching follows the shortest path in a ring topology. When the ring is broken, the stack recalculates the forwarding path and then resumes the flow of traffic within a few seconds.
In a ring topology, all stack members must have two stacking ports; however, in a linear topology, both end units use only one stacking port, leaving the other port available as a data port.
Hope this helps.