Sony is rolling out 1 January 2020 Android security patches to the Xperia 1 and Xperia 5 smartphones. Both phones have received new firmware that moves the build number from 55.1.A.0.748 to version 55.1.A.3.49. Sony does not include any changelogs, which remains a frustration, but there do not look like there are any other changes. If you have updated, please let us know your impressions in the comments below.
Recent Sony Xperia firmware updates
Xperia 1 and Xperia 5
New update: 55.1.A.3.49 (Security patch: 1 January 2020)
Old update: 55.1.A.0.748 (Security patch: 1 November 2019)
New update: 49.0.A.6.107 (Security patch: 5 December 2019)
Old update: 49.0.A.6.102 (Security patch: 5 December 2019)