MQ Explorer is a Java based application so does not rely on the GSKit version but instead on Java's underlying JSSE implementation.
In general a non-java applications using MQ v22.214.171.124 could utilize TLS1.2 cipherspecs if they have installed GSKit 8 and have specified the
AltGSKit=YES setting in the
SSL stanza of the
mqclient.ini, this does not apply however to Java applications like MQ Explorer.
Supporting this is the following info in APAR IT00326: WMQ V7.X EXPLORER IS NOT ABLE TO CONFIGURE A CIPHER SPECIFICATION SUPPORTED BY GSKIT V8 FOR A V7.0.1 QUEUE MANAGER talking about using MQ Explorer to configure channels on a 126.96.36.199 or later queue manager that has the
AltGSKit=YES setting in place in the
SSL stanza of the
qm.ini. (bolded the key info below):
The WebSphere MQ Explorer has been updated to allow the configuration
of the following CipherSpecs on a channel definition when connected to
a version 7.0.1 queue manager:
These CipherSpecs require GSKit 8 to be configured on the queue
manager. Attempting to set these CipherSpecs for a channel definition
on a version 7.0.1 queue manager which is using GSKit 7 will cause MQ
Explorer to display an AMQ4126 error.
It should be noted that WebSphere MQ Explorer version 7.0.1 does not
support the use of these three CipherSpecs for its communications with
the queue manager over a ServerConnection channel.
The IBM MQ Classes for Java does not support SHA2 cipherspecs until MQ v7.1.
I would recommend you download the standalone MQ v9.1 Explorer SupportPac, you can find it here: MS0T: IBM MQ Explorer.
The versions listed below are all End of Support at this time and v8 is going to be end of support on April 30th 2020:
V7.0 EOS: September 30 2015
V7.1 EOS: April 30 2017
V7.5 EOS: April 30 2018
V8.0 EOS: April 30 2020