Since you have L3 switches, and links from S4 to S1 are Ethernet, it's possible you don't need R4.
Since R1 and R2 links to R3 are serial, they likely offer less bandwidth than your FE links, so, you might want to consider for those links, QoS and/or multiple serial links and/or MAN/WAN Ethernet to mitigate the likely bottlenecks of those links.
As Balaji notes, you don't have any L2 loops, so STP, isn't needed. Further, again, as you're using L3 switches, if you continue to do so, you could route between them further avoiding L2 loops and better using any redundant path bandwidth. That said, even when STP isn't needed, by design, it's always a very good idea to have it enable to preclude the creation of a L2 loop, by accident.
Cisco DNA Center version 2.2.2.x includes the features and improvements that
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When using Cisco cellular modules with a SIM card an APN must be provided. The APN cannot be stored in the SIM card and is supplied by your SIM card provider. Cisco cellular software contains a database of well-known APNs based on the country and ...
Cisco 3850: IOS-XE/Firmware Upgrade
This procedure is aimed at Cisco 3850 switch ONLY.
IOS-XE Bundle Mode is not covered.
9300, 9500 (vanilla & high-performance), ISR 1k, ISR 4k and ASR is not covered.
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