tried your updated heatermeterclient files and all I get is a compiler error:
Arduino: 1.8.13 (Mac OS X), Board: "LOLIN(WEMOS) D1 R2 & mini, 80 MHz, Flash, Disabled (new aborts on oom), Disabled, All SSL ciphers (most compatible), 32KB cache + 32KB IRAM (balanced), Use pgm_read macros for IRAM/PROGMEM, 4MB (FS:2MB OTA:~1019KB), v2 Lower Memory, Disabled, None, Only Sketch, 460800"
In file included from /Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Variant/VariantContent.hpp:11,
from /Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Variant/VariantSlot.hpp:11,
from /Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Memory/MemoryPool.hpp:10,
from /Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Variant/VariantData.hpp:7,
from /Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Variant/SlotFunctions.hpp:8,
from /Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Array/ArrayIterator.hpp:7,
from /Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Array/ArrayRef.hpp:8,
from /Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson.hpp:17,
from /Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson.h:9,
from sketch/HeaterMeterClient.h:11,
from sketch/HeaterMeterClient.cpp:1:
/Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Variant/VariantAs.hpp: In instantiation of 'typename ArduinoJson6173_91::enable_if<(ArduinoJson6173_91::is_integral<T>::value && (! ArduinoJson6173_91::is_same<bool, T>::value)), T>::type ArduinoJson6173_91::variantAs(const ArduinoJson6173_91::VariantData*) [with T = long long int; typename ArduinoJson6173_91::enable_if<(ArduinoJson6173_91::is_integral<T>::value && (! ArduinoJson6173_91::is_same<bool, T>::value)), T>::type = long long int]':
/Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Variant/VariantAs.hpp:94:22: required from 'T ArduinoJson6173_91::variantAs(ArduinoJson6173_91::VariantData*, ArduinoJson6173_91::MemoryPool*) [with T = long long int]'
/Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Variant/VariantRef.hpp:259:24: required from 'ArduinoJson6173_91::VariantRef:

perator T() const [with T = long long int]'
/Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Object/MemberProxy.hpp:77:30: required from 'ArduinoJson6173_91::MemberProxy<TParent, TStringRef>:

perator T() const [with T = long long int; TObject = ArduinoJson6173_91::JsonDocument&; TStringRef = const char*]'
sketch/HeaterMeterClient.cpp:166:31: required from here
/Users/temp/Documents/Arduino/libraries/ArduinoJson/src/ArduinoJson/Variant/VariantAs.hpp:59:3: error: static assertion failed: To use 64-bit integers with ArduinoJson, you must set ARDUINOJSON_USE_LONG_LONG to 1. See
https://arduinojson.org/v6/api/config/use_long_long/
59 | ARDUINOJSON_ASSERT_INTEGER_TYPE_IS_SUPPORTED(T);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
exit status 1
Error compiling for board LOLIN(WEMOS) D1 R2 & mini.
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