Here is a brief history of Symbian OS.
Psion: In 1980, Psion was founded by David Potter.
EPOC: EPOC is family of graphical OS developed by Psion for portable device
EPOC 16: EPOC 16 was the OS developed by Psion in 1980 and early 1990s for Psion's SIBO devices like MC200, MC400,Series3 etc.
EPOC-32: The first version of EPOC32,Release1 appeared on Psion series 5 in 1997.
EPOC 32 OS, at that time simply referred to EPOC was later renames to Symbian OS.In 1998, Psion software became Symbian, a major joint venture between Psion and Ericsson, Nokia, Motorola. EPOC simply become Symbian OS.
EPOC-32: The first version of EPOC32,Release1 appeared on Psion series 5 in 1997.
EPOC 32 OS, at that time simply referred to EPOC was later renames to Symbian OS.In 1998, Psion software became Symbian, a major joint venture between Psion and Ericsson, Nokia, Motorola. EPOC simply become Symbian OS.
EPOC OS Release 1-3 (ER1, ER3): The Series 5 device released in june 1997, used it.
EPOC Release 4: The device Osaris used it.
EPOC Release 5: The device like Psion series 5mx, series7 were released using ER5.
ER5u: Ericsson R380 was released using ER5u in november 2000.
Symbian os v6.0 and 6.1: This release sometime is called ER6. The first Symbian OS phone 9210 was released in june 2001.
Symbian OS 7.0 and 7.0s: First released in 2003 which was important release. It also added EDGE.
Symbian OS 8.0: First shipped in 2004. It included new APIs to suppor CDMA,3G, DVB-H.
Symbian OS 8.1: Basically a clean up version of 8.0. Most famous smartphone featuring 8.1a was N90 in 2005.
Symbian OS 9.0: This version was used for internel purpose only.This version has no binary code compatibility with previous version.
Symbian OS 9.1: Relesed early 2005. It includes a controversial mandatory code signing. Developers need to retool and recode. Support for bluetooth 2.0(was 1.2)
Symbian OS 9.2: Relesed Q1 2006. S60 3rd editions, Feature Pack 1 have os 9.2.
Symbian OS 9.3: Relesed on 12 july2006. Native support for WiFi 802.11,HSDPA.
Symbian OS 9.4: Announced on March 2007. SQL support. Used asthe basis for Symbian^1, the firstsymbian platform released also know as S60 5th edition.
Symbian OS 9.5: native support for mobile TV broadcast in DVB-H and ISDB-T format. S60 wikipedia
