V4 analysis from V3V4 reading

I have a set of demultiplexed Illuminina V3V4 reads fastqs.
Even though the reads cover V3V4(~465bp), I want to focus and analyze only V4 regions to compare previous public data.
How should I proceed??
Thanks

An off-topic reply has been merged into an existing topic: Only V4 analysis from V3V4 reading

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