The HubV2 currently only supports 32 directly connected end devices. If you were to first connect 32 end devices (for example the sengled bulbs) you wouldn’t be able to connect a 33rd device until you join a router to the network. However the routers don’t count against the 32 end device limit and you can add as many routers as you want/need. Each router will support a limited number of end devices and that number will vary by model.
We tried to bump the end device limit to 64 in the 0.18 hub firmware release but there was an unrelated regression in the Zigbee firmware and so we had to revert back to the Zigbee firmware that has the 32 device limit. We would like to increase that limit in the future but unfortunately I can’t say right now when that might happen.