On July 3, QGIS 4.2 based on the latest QT6 was officially released, while the QT5-based version 3.44.12 also received an update. Is QGIS 4.2 worth upgrading to? Are there any pitfalls? Today, I will briefly sort this out for you. Fellow QGIS users, please take note.

About QGIS 4.2.0

This is another major version after 4.0. The 4.2 release is named "Belém do Pará". The QGIS community has a tradition of naming each major release after the city that hosts the QGIS Developer Meeting or related academic conference. This version is named after Belém, the capital of Pará state in Brazil, in honor of an important GIS conference held there.

QGIS 4.2 focuses on upgrading the full suite of 3D scene and point cloud tools, and improving the ability to read cloud remote sensing data such as COG and STAC. For 2D cartography, it adds layout charts and PDF layer export. The processing model adds real-time feature statistics and several new spatial algorithms, optimizing rendering speeds for various vector and raster data. It also enhances the stability of network services and database connections, expands coordinate reference systems and expression functions, improves the interface and QGIS Server, and fixes numerous crashes and display bugs.

Overall, QGIS 4.2 still revolves around expanding 3D capabilities and fixing legacy issues from the QT6 upgrade. There is also a major change worth mentioning separately: the user profile directory of QGIS 4 is now completely isolated from QGIS 3. On first launch, it copies the current user configuration once, after which the two no longer sync. This means that from a user configuration perspective, QGIS 3.x and QGIS 4.x will be two separate pieces of software going forward.

Current Issues with QGIS 4.2

I have been using QGIS 4.0.2 for quite some time, and the common functions are essentially problem-free (though I use it less and have few essential plugins). The main issue troubling me is the lack of Chinese translation. This has been reported many times in the community, but version 4.2.0 still does not support it.

However, I found a workaround. Locate the following path. If you are a Mac user, the path is:

~/Library/Application Support/QGIS/QGIS4

Linux user path:

~/.local/share/QGIS/QGIS4/

Windows user path:

C:\Users\YourUserName\AppData\Roaming\QGIS\QGIS4\

Create a new file named startup.py in this directory and write the following content:

from qgis.PyQt.QtCore import QTranslator, QCoreApplication
import sys

# Choose the translation file path according to your system, modify based on your actual installation location
if sys.platform == "darwin":
    # macOS official installer (version number varies with .app name)
    qm_file = "/Applications/QGIS-final-4_2_0.app/Contents/Resources/qgis/i18n/qgis_zh-Hans.qm"
elif sys.platform == "win32":
    # Windows OSGeo4W installation
    qm_file = r"C:\OSGeo4W64\apps\qgis\i18n\qgis_zh-Hans.qm"
    # Windows standalone installer (verify the version number in the path)
    # qm_file = r"C:\Program Files\QGIS 4.2.0\apps\qgis\i18n\qgis_zh-Hans.qm"
else:
    # Linux distribution package manager installation (common path for Debian/Ubuntu etc.)
    qm_file = "/usr/share/qgis/i18n/qgis_zh-Hans.qm"

translator = QTranslator()
load_ok = translator.load(qm_file)

if load_ok:
    print("qgis_zh-Hans.qm loaded successfully")
    QCoreApplication.instance().installTranslator(translator)
else:
    print("Load failed, please check the file path")

After running, it looks like this:

This method is only a temporary solution, as many parts remain in English. If you have a better method, please let us know.

P.S. I only verified this on macOS; paths on other systems may vary. Please adjust accordingly.

Why QGIS 4.2 Deserves Attention

According to the official roadmap, the LTR (Long Term Release) for QGIS 4.x is expected around October 30, 2026. The current tentative version is 4.2.4, meaning we are only four minor versions away from the LTR QGIS 4.x. So if you plan to keep upgrading, you should pay attention to this version and start preparing for simple migration work in advance.

Summary

Additionally, the QT5-based QGIS 3.x branch also released QGIS 3.44.12 on the same day, which mainly includes routine bug fixes and patch updates—nothing to elaborate on here. The arrival of QGIS 4.2 means that in a few months, we will have the LTR version of QGIS 4. Are you ready?