Please note, the following known issues:
native bookmark tags are not supported in Firefox’s bookmarks API and so are not supported by xBrowserSync. Any existing native tags will be lost when using xBrowserSync
Please see this list for more information. Also we recommend using Firefox v69 or later due to additional bugs in Firefox's bookmarks API in v68 and earlier. What’s new in version 1.5.2:

Fixed bug where startup process can be triggered twice in some instances which can cause data loss/corruption
Fixed bug where checking for updates whilst syncs are being processed can trigger a local refresh whilst event listeners are enabled
Fixed bug when checking network connection status
Fixed Firefox bug where moving multiple bookmarks results in corrupt sync data
Fixed Firefox bug where sync data is corrupted when creating new folders via native bookmarking functionality
Fixed Firefox bug where sync is executed twice when moving bookmarks
Improved sync engine handling of large amounts of simultaneous changes
Updated sync engine so that remote data is only updated once after all queued syncs have been processed
Fixed Android bug when retrieving metadata fails with an error and bookmark panel does not display
Fixed Android bug where loading dialog displays before form is shown when adding bookmark by sharing to app
Fixed Android bug where status bar disappears when loading metadata
Fixed Android bug where error message not displaying when retrieving metadata for shared bookmark fails
Added ability to cancel sync when extension window is opened during push sync
Added a delay on checking for sync updates on startup to allow browser to init connection
Changed check for updates period back to 15 minutes
Fixed bug where disabling sync from extension window doesn't disable properly in background
Fixed potential messaging bugs when extension window is opened during sync
Fixed bug in metadata collection where description displays encoded characters
Fixed bug where encoded characters are displayed in tags after getting bookmark metadata
Fixed bug where password fields highlight spelling issues when set to show password
Added option of checking for app updates to Preferences section in Settings panel
Fixed bug where sync id is not displayed when disabling sync just after creating a new sync
Added ability to click native alerts to open links
Fixed bug when disabling sync, Settings panel flickers and Login panel displays after slight delay
Fixed bug where only first bookmark tag in field shows autocomplete
Improved handling of syncing when offline for desktop platforms
Moved sync bookmarks toolbar setting to prefs panel
Improved sync UI by adding abiity to update service URL when creating a new sync/entering sync credentials
Added confirmation panel displaying service info when updating service URL
Updated Sync ID QR code to now also include service URL and updated Android scanning functionality to read new QR code format
Updated layout CSS to improve handling of browser page zoom
Many, many more minor enhancements and bug fixes

For full release history visit github.com/xbrowsersync/app/releases