Hi @sharad,
We have notified AWS about it, but for now it has not been published yet on Lightsail. You could use our standalone installer to install the LAMP with the latest PHP version. To do that you need to stop the services first:
sudo /opt/bitnami/ctlscript.sh stop
Then backup/rename the /opt/bitnami folder:
sudo mv /opt/bitnami/ /opt/bitnami.bak
And download the latest version:
wget https://bitnami.com/redirect/to/770107/bitnami-lampstack-7.3.11-0-linux-x64-installer.run
And run it with sudo:
sudo ./bitnami-lampstack-7.3.11-0-linux-x64-installer.run --prefix /opt/bitnami
Regards,
Michiel