Hi,

On a freshly installed Debian 10.9 amd64 system, strictly following the build-from-sources procedure - just for reference:

apt-get update
apt-get upgrade
curl -fsSL https://deb.nodesource.com/setup_14.x | bash -
apt-get install gcc g++ make
apt-get install -y nodejs
curl -sL https://dl.yarnpkg.com/debian/pubkey.gpg | gpg --dearmor | tee /usr/share/keyrings/yarnkey.gpg >/dev/null
echo "deb [signed-by=/usr/share/keyrings/yarnkey.gpg] https://dl.yarnpkg.com/debian stable main" | tee /etc/apt/sources.list.d/yarn.list
apt-get update && sudo apt-get install yarn
apt-get install build-essential redis-server libpng-dev git python-minimal libvhdi-utils lvm2 cifs-utils

yarn build

fails with

Using polyfills: No polyfills were added, since the `useBuiltIns` option was not set.
Successfully compiled 131 files with Babel (31694ms).
[09:53:39] Finished 'buildStyles' after 14 s
[09:53:39] Finished 'copyAssets' after 15 s
[09:54:44] 'buildScripts' errored after 1.32 min
[09:54:44] GulpUglifyError: unable to minify JavaScript
Caused by: SyntaxError: Unexpected token name «await», expected punc «(»
File: /home/xci/xen-orchestra/packages/xo-web/src/index.js
Line: 219419
Col: 8
[09:54:44] 'build' errored after 1.32 min
* xo-web:build − Error: 1
✖ 1
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

(I had a fully working Debian Stretch VM with xen-orchestra, but on the last 'git pull --ff-only' I was forced to upgrade nodejs from 14.6 to 14.7, which failed, so I decided to start from scratch).

Any ideas?