Office 365 stop supporting TLS 1.0/1.1 at March 1st 2018.
It may required to applying windows patch and registry settings
(for application targetting .NET 4.6 or prior version)
Then, it need to ensure old protocols are not used.
Use following filter to show only SSL/TLS ClientHello traffics.
(SSL) or (TLS.records[0].fragment[0].msg_type == TLS.HandshakeType.client_hello)
And then, Check TLS version by adding following value to GridView column.
TLS.records[0].fragment[0].body.client_version
Note: there is TLS version at "TLS.records[0].version" also. but it seems not be used.
Windows OS support network capture by default. Execute following command to start network capture (with admin previlage)
netsh trace start tracefile=C:\temp\tcp_traffice.etl Protocol=TCP capture=yes maxsize=200 filemode=circular overwrite=yes report=no
When operation finished. stop netwok capture with following command.
netsh trace stop
Sample code to test old protocols
[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]::Tls # Use TLS 1.0
Invoke-RestMethod -Uri "<Url>"