address PR feedback

Signed-off-by: brunobat <[email protected]>

specification/sdk-environment-variables.md

@@ -16,11 +16,11 @@ The SDK MUST interpret an empty value of an environment variable the same way as
 
 ### Boolean value
 
-Any value that represents a Boolean MUST be set to true only by the case-insensitive string "true", meaning "True" or "TRUE" are also accepted, as true.
+Any value that represents a Boolean MUST be set to true only by the case-insensitive string `"true"`, meaning `"True"` or `"TRUE"` are also accepted, as true.
 An SDK MUST NOT extend this definition and define additional values that are interpreted as true.
 Any value not explicitly defined here as a true value, including unset and empty values, MUST be interpreted as false.
-If any value other than a true value, case insensitive string `"false"`, empty, or unset is used, a warning SHOULD be logged to inform users about the fallback to false being applied.
-All Boolean environment variables SHOULD be named and defined such that false is the expected safe default behavior.
+If any value other than a true value, case-insensitive string `"false"`, empty, or unset is used, a warning SHOULD be logged to inform users about the fallback to false being applied.
+All Boolean environment variables SHOULD be named and defined such that false is the expected safe default behavior. Renaming and changing the default value MUST not happen between major versions.
 
 ### Numeric value