The largest 4G network in the UK, EE, have just announced two new mobile WiFi devices along with some new plans.
Meet the 4GEE WiFi and 4GEE WiFi Mini. They are now smaller and lighter than previous versions. The 4GEE WiFi is CAT 12 enabled up to 600Mbps) whilst the 4GEE WiFi Mini is Cat 7 (up to 300Mbps). This means that the a high capacity connection to 20 devices simultaneously on either device.
Source: EE announce new MiFi devices