Author: Rudi Stoeger Ladies and Gentlemen My colleague Uwe Hessels upgraded the firmware from 8.71/3.822 to 8.71/3.823 in the LEICA GRX100GGPRO in the SOFI GNSS Permanent Tracking Station Sofia, Bulgaria, 2014-07-21T13:55Z. With best regards Rudi Stöger