First of all: NKN assets are safe, since we are doing the node software upgrade in a phased and safe way. The consensus algorithm has been proven to be very reliable, since our mainnet has been running since July 2019 with very few interruptions.
Secondly: Data transmission over NKN is off chain and still work as usual. This is one of the key strength of NKN network.
What caused the blockchain halt: The halt was initially caused by a logging issue: the default loggers will eat up all node CPU and disk IO if a node receives high throughput invalid data stream, and prevent block proposal from propagating to the network. Although the issue was fixed on the same day as the halt, upgrading and recovering the network is challenging and took the majority of our time as we need to work with multiple parties like mining pools, individual miners, etc.
If you are a miner, please kindly update your node software to the latest!
Again thanks for your patience and stay tuned!