The hardware that was running BI3 has kicked the bucket. So a new rebuild is in order. What is the upgrade path license-wise? Is there a discount from Blue Iris or has it been too long? The license was never upgraded to BI4.
Pretty sure there's no path from v3 or even v4 because how long v5 has been out now. But the improvements over v4 and especially v3 make it money well spent.
I've used v3 beginning in 2014, v4 (2015?) and now v5 since late 2019 and I am a big, big fan...especially since substream RTSP support was added in May of 2020. It can lower CPU usage drastically.