The Treasury calculates the inflation component of I bonds for the 6-month period starting on November based on the CPI-U change from March to September. From last Friday's inflation report, September CPI-U can be computed, and it's low: only 0.74% (annualized). The Savings Bond Advisor has a good overview of this calculation
So if you buy I bonds before November, you'll get a fixed rate of 0.20% plus 6 months of the current inflation component (1.54%) for a 6-month yield of 1.74%. For the next 6 months, the new inflation component would be added to the fixed rate. That gives a second 6-month yield of 0.94%.
I have a feeling the Treasury won't be raising the fixed rate in November.