According to different equipment and systems, there are mainly the following methods:
First, Apple ios system devices:
1. Open iTools, enter the library, find QQ, click the drop-down arrow, select the old QQ installed with iTools before, and click Demote.
2. Apple mobile phone downloads "Apple Quick Assistant" and directly downloads and installs it.
Second, Android system (most smart phones at present):
If you remember the version history, you can directly download it through the browser search software+version number.
You can download the software version history provided by application stores such as Anzhi Market.
Third, computer equipment:
Search the browser for the downloaded software+version number. The software installation package of windows system is in exe format, so pay attention to the download format.