Full list of differences found in [this compare.](https://github.com/open-telemetry/opentelemetry-proto/compare/v0.7.0...v0.8.0)
Historical breaking change notice
Release 0.8 was the last in the line of releases marked as "unstable".
This release broke compatibility in more ways than were recognized and
documented at the time of its release. In particular, 278 created
the `NumberDataPoint` type and used it in several locations in place
of the former `DoubleDataPoint`. The new `oneof` in `NumberDataPoint`
re-used the former `DoubleDataPoint` tag number, which means that
pre-0.8 `DoubleSum` and `DoubleGauge` points would parse correctly as
a 0.8 `Sum` and `Gauge` points containing double-valued numbers.
However, by virtue of a `syntax = "proto3"` declaration, the protocol
compiler for all versions of OTLP have not included field presence,
which means 0 values are not serialized. **The result is that valid
OTLP 0.7 `DoubleSum` and `DoubleGauge` points would not parse
correctly as OTLP 0.8 data.** Instead, they parse as
`NumberDataPoint` with a missing value in the `oneof` field.
Changed: Metrics
* :stop_sign: [DEPRECATION] Deprecate IntSum, IntGauge, and IntDataPoint (278)
* :stop_sign: [DEPRECATION] Deprecate IntExemplar (281)
* :stop_sign: [DEPRECATION] Deprecate IntHistogram (270)
* :stop_sign: [BREAKING] Rename DoubleGauge to Gauge (278)
* :stop_sign: [BREAKING] Rename DoubleSum to Sum (278)
* :stop_sign: [BREAKING] Rename DoubleDataPoint to NumberDataPoint (278)
* :stop_sign: [BREAKING] Rename DoubleSummary to Summary (269)
* :stop_sign: [BREAKING] Rename DoubleExemplar to Exemplar (281)
* :stop_sign: [BREAKING] Rename DoubleHistogram to Histogram (270)
* :stop_sign: [DATA MODEL CHANGE] Make explicit bounds compatible with OM/Prometheus (262)