Unlock Endpoint not being called after Iframe is closed in WOPI, when upgraded Office Online Server to version to 16.0.10338.20039.

Question

Hi All,
We have integrated Word application and editing docs using WOPI Integration in our website. I am aware of the fact that in earlier versions of WOPI, OOS, there is a known bug that Unlock endpoint does not get called after the editing session is closed in Chrome and Edge browser.

I installed the OOS version 16.0.10373.20000, in that version, this bug was resolved for docx, xlsx, and pptx files and was working fine.
But since last week, after upgrading the OOS version to 16.0.10338.20039, Unlock endpoint is not getting called after the editing session is closed in Chrome and Edge browser. Its is working fine in the Firefox browser. Can anyone tell what could be the reason behind this?
Or any suggestions on how to move back to version 16.0.10373.20000.

I am setting these fields in my CheckInfoFile endpoints
responseData = new CheckFileInfoResponse()
{
// required CheckFileInfo properties
BaseFileName = dbFile.FileName,
OwnerId = userId,
Size = dbFile.FileContent.Length,
UserId = _userId,
Version = version,
ReadOnly = false,
UserCanWrite = true,
SupportsUpdate = true,
UserCanNotWriteRelative = true,
SupportsLocks = true,
ClientUrl = clientUrl,
SupportsFileCreation = true,
HostViewUrl = HostView,
HostEditUrl = HostEdit,
UserFriendlyName = UserDisplayName,
SupportsGetLock = true
};

Answer 1

HI Ajitesh

Make sure you also have latest security patch applied. Make sure to download Security Update for Microsoft Office Online Server (KB5001943) farm-deployment dated 2021 June 3 from following site https://www.catalog.update.microsoft.com/Search.aspx?q=Office+Online+Server

Do follow the steps outline here Security Update for Microsoft Office Online Server (KB5001943) farm-deployment

Hung-Chun Yu
Open Specifications Support, Microsoft.