would like to know some support details on Big-IP 3600 (C103) platform running software version - .12.1.2

Perhaps the following two solution articles may help?

 

K4309: F5 platform lifecycle support policy

 

K9476: The F5 hardware/software compatibility matrix

 

Hi,

 

• BIG-IP software versions supported by the platform: 9.4.5 to 12.1.2
• End of Sale: 01-Oct-2014
• End of New Software Support (EoNSS): 01-Oct-2016
• Platform End of Software Dev (EoSD): 01-Oct-2017
• Platform End of Technical Support (EoTS): 01-Oct-2021
• End of RMA (EoRMA): 01-Oct-2021

And if you need more details about BIG-IP software support policy, check this:

 

https://support.f5.com/csp/article/K5903

 

End of Technical Support for version supported by 3600 (12.1.2): - End of Software Development: 18-May-2021 - End of Technical Support: 18-May-2022 - Latest maintenance release: 12.1.3

 

Hope it's clear, let me know if you need additional info.

 

For info:

 

https://support.f5.com/csp/article/K9476

 

https://support.f5.com/csp/article/K4309