Yesterday I did the mapping as suggested by @ShubhS9 see the results below. Many codes are missing!!! I am surprised @nithin that Zerodha rather then accepting the suggestion has so much of resistance in doing such a simple thing.
Year/NSECOde/Price at launch/Zerodha Code
2015 SGBNOV23 2,684.00
2016 SGBMAR24 2,916.00
2016 SGBNOV24 2,957.00
2016 SGBAUG24 3,119.00
2016 SGBSEP24 3,150.00
2016 SGBFEB24 2,600.00
2017 SGBDEC25 2,911.00 SGBDEC25
2017 SGBNOV25VI 2,895.00 SGBNOV25VI
2017 SGBOCT25V 2,921.00 SGBOCT25V
2017 SGBNOV25IX 2,914.00 SGBNOV25IX
2017 SGBNOV258 2,911.00 SGBNOV258
2017 SGBOCT25IV 2,937.00 SGBOCT25IV
2017 SGBOCT25 2,906.00 SGBOCT25
2017 SGBMAR25 2,893.00
2017 SGBJUL25 2,780.00
2017 SGBMAY25 2,901.00
2017 SGBNOV25 2,884.00 SGBNOV25
2017 SGBDEC25XI 2,902.00 SGBDEC25XI
2017 SGBDEC2513 2,816.00 SGBDEC2513
2017 SGBDEC2512 2,840.00 SGBDEC2512
2018 SGBMAY26 3,064.00 SGBMAY26
2018 SGBJAN26 2,831.00 SGBJAN26
2018 SGBOCT26 3,096.00 SGBOCT26
2018 SGBDEC26 3,069.00 SGBDEC26
2018 SGBNOV26 3,133.00 SGBNOV26
2019 SGBOCT27VI -
2019 SGBAUG27 - SGBAUG27
2019 SGBFEB27 3,276.00 SGBFEB27
2019 SGBOCT27 - SGBOCT27
2019 SGBJUL27 - SGBJUL27
2019 SGBDC27VII -
2019 SGBSEP27 - SGBSEP27
2019 SGBJAN27 3,164.00 SGBJAN27
2019 SGBJUN27 - SGBJUN27
2020 SGBSEP28VI - SGBSEP28VI
2020 SGBJUN28 -
2020 SGBAUG28V -
2020 SGBJUL28IV -
2020 SGBAPR28I -
2020 SGBMAY28 -
2020 SGBOC28VII - SGBOC28VII
2020 SGBJ28VIII -
2020 SGBMAR28X -
2020 SGBFEB28IX -