Thank you for your advice. I changed the I2C address at line 34 in the AOSongAM2315.cpp. I got this output ..
Current logger time is 2024-05-13T15:02:43-06:00
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EnviroDIY Mayfly at EnviroDIY Mayfly reports batteryVoltage is 4.715 volt
SensirionSHT4x at I2C_0x44 reports relativeHumidity is 39.09 percent
signalPercent is calculated to be 97 percent
SensirionSHT4x at I2C_0x44 reports temperature is 24.72 degreeCelsius
AOSongAM2315 at I2C_0x38 reports temperature is -9999.0 degreeCelsius
AOSongAM2315 at I2C_0x38 reports relativeHumidity is -9999.0 percent
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So it looks like the address change is in effect but sensor values are still -9999.
Do you have any advice or ideas for my next troubleshooting effort?