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What's New in Hyperledger Fabric v1.4
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The following features are included in this release:

Fabric operations service
A new HTTP based "operations" endpoint has been implemented on the orderer and
the peer. The endpoint exposes APIs to check the server's health, to query
and modify the logging level of the process, and, when configured, to expose
Fabric metrics.

FAB-3388 - Operational metrics for Fabric components
The peer and orderer have been instrumented to provide basic operational
metrics. The metrics can be surfaced for consumption by Prometheus or StatsD.

FAB-10851 - Health check endpoint
The orderer and the peer now provide a mechanism to check the health of the
process via an HTTP request. Requests to GET /healthz on the operations
endpoint will complete with a status 200 OK when the server believes it is
healthy. When a health check fails, the server will respond with a 503 Service
Unavailable and a JSON payload indicating which component detected an issue.
The types of health checks that are performed will be extended over time.

FAB-12265 - Dynamic log levels
The orderer and the peer now provide a mechanism to get and update the active
logging specification of the server. Requests to GET /logspec on the
operations endpoint will return with a JSON payload that contains the active
spec. When a JSON payload of `{"spec":"the-log-spec"}` is sent as the body of
a PUT /logspec request, the active logging spec will be updated.

FAB-12357 - Updates to logging
In earlier versions of Fabric, loggers were associated with named components
and configuration would control the active level of each logger. While this
model works in theory, because of the configuration management libraries used
by Fabric and the structure of the Fabric code base, in practice it had a
number of issues.
With 1.4, we're changing the model slightly. Instead of associating loggers
with components, we are naming loggers and to help avoid side effects during
initialization, the logging configuration is no longer obtained from the
fabric configuration system but from environment variables that define
the logging specification and log format.
The log specification is a single string that consists of colon separated
tokens. Each token declares one or more logger name prefixes (separated by
commas) and an optional log level. When the logger name prefix ends with a
period, it indicates that the log level should only apply to the logger with
that exact name without the trailing period. When the logger name pattern is
omitted, it specifies the default log level. In cases where multiple entries
reference the same name pattern or multiple instances of a default are
provided, the last specification takes precedence.

FAB-12363 - Logging for gRPC interactions
The orderer and the peer now provide logging (INFO level) for each gRPC
interaction completed.

FAB-12372 - Obtain Go routine stacks without termination
When SIGUSR1 is received by the peer or the orderer, the state of all go
routines will be captured and logged at the INFO level. This collection
activity will not terminate the process.

FAB-5093 - Private data reconciliation
Allows peers for organizations that are added to private data collections
to retrieve the private data for prior transactions to which they now are
entitled. This feature is only supported on peers that have joined
a channel since v1.4.

FAB-11409 - Private data client access control
Ability to automatically enforce access control within chaincode based
on the client organization collection membership without having to
write specific chaincode logic. This feature is configured by using
the collection configuration property memberOnlyRead:true. If you have
a mixed network of v1.4 peers and prior release peers, the prior
release peers will not honor this configuration until they are upgraded
to v1.4.

Changes, Known Issues, and Workarounds
--------------------------------------

FAB-12357 - Updates to logging
Instead of using logging.level and CORE_LOGGING_LEVEL to control the logging
level for the peer, and General.LogLevel or ORDERER_GENERAL_LOGLEVEL to
control logging at the orderer, both processes now use the FABRIC_LOGGING_SPEC
environment variable to acquire the initial logging specification for the
server. Existing logging configuration should be converted to the new model.

FAB-12489 - peer logging command updates
The `getlevel`, `setlevel`, and `revertlevels` subcommands of the `peer
logging` command are deprecated and users should migrate to the operations
server.
The behavior of `setlevel` has also changed slightly. The previous
implementation would treat the `logger` argument as a regular expression and
apply the new log level to all loggers that matched the expression. The
updated implementation treats the `logger` argument as a logger name and
appends it to the active logging spec at the indicated level.

FAB-12088 - Java chaincode support on s390 architecture
Java chaincode support is not yet available on s390 architecture.

FAB-12134 Same chaincode source receiving fingerprint mismatch error
Chaincode installed in different ways may result in "chaincode fingerprint
mismatch data mismatch" error upon instantiation.  This may happen when
installing chaincode by using different SDKs. To workaround the problem,
package the chaincode prior to installation and instantiation, by using
the "peer chaincode package" command.

Known Vulnerabilities
---------------------
FAB-8664 - Peer should detect and react when its org has been removed
This is a relatively low severity problem, because it requires a significant
conspiracy of network admins, but it will be addressed in a future release.

Resolved Vulnerabilities
------------------------
None.

Other improvements and fixes
----------------------------
Updated to Go version 1.11.1
Updated baseimage version to 0.4.14

For the full list of improvements and fixes, refer to the release change log:
https://github.com/hyperledger/fabric/blob/master/CHANGELOG.md#v140-rc2