When you buy a SRX340 (HW+SW SKU) you are entitled to get the latest version of the software within 15 days. On top you will get 1 year warranty on the hardware (read hardware + software part of https://www.juniper.net/support/warranty/ if you need more details).
The minimum level of support is "Core Support" which shall be purchased for the SW SKU. If you buy SRX340-JSB software you will need 1 x SVC-COR-SRX340JSB support SKU. This will give you 24x7 JTAC access and right to download latest software versions. If you want, you can then buy "Core plus" HW support for the hardware SKU which gives you return-to-factory hardware replacement rights. Core Plus for the SRX340 is covered by the SVC-CP-SRX340HW SKU.
I hope this answers your question in regards to support 🙂
#SRX#support