diff --git a/doc/using.but b/doc/using.but
index 3171de99..c595c153 100644
--- a/doc/using.but
+++ b/doc/using.but
@@ -1185,11 +1185,10 @@ box for host certification authorities, as described in
 \k{config-ssh-kex-cert}. When you dismiss that dialog box, PuTTY will
 terminate.
 
-\S2{using-cmdline-legacy-console} \i{\c{-legacy-stdio-prompts}},
-\i{\c{-legacy-charset-handling}}: handle Windows console prompts like
-older versions of PuTTY
+\S2{using-cmdline-legacy-stdio-prompts} \i{\c{-legacy-stdio-prompts}}:
+handle Windows console prompts like older versions of PuTTY
 
-These options apply to all of PSCP, PSFTP and Plink on Windows: all
+This option applies to all of PSCP, PSFTP and Plink on Windows: all
 the tools in the PuTTY suite that run in a Windows console and make
 SSH connections.
 
@@ -1204,12 +1203,13 @@ responses will be read from the console (and not from where you've
 redirected your input).
 
 Another advantage of reading directly from the Windows console is that
-the tools can read input as Unicode. So this also allows you to enter
-usernames and passwords that contain characters not in the Windows
-system's default character set.
+the tools can read input as \i{Unicode}. So this also allows you to
+enter usernames and passwords that contain characters not in the
+Windows system's default character set.
 
-In older versions of PuTTY, the prompts used the tool's ordinary I/O
-handles, so prompt output and user responses could be redirected.
+In versions of the PuTTY tools up to and including 0.81, the prompts
+used the tool's ordinary I/O handles, so prompt output and user
+responses could be redirected.
 
 We think the new behaviour is more likely to be useful. For example,
 if you have a local command that generates output, and you want to
@@ -1225,16 +1225,47 @@ more awkward.
 
 However, we recognise that people may have customised complicated
 workflows around the old behaviour. So if you need to switch back to
-it, there are two options to switch some or all of the behaviour back
-to the old way:
+it, you can do so by specifying \c{-legacy-stdio-prompts} on the
+command-line.
 
-\c{-legacy-charset-handling} makes the tools read prompt responses in
-the system's default character set instead of Unicode. If the new
-Unicode-based input causes a username or password not to work as you
-expected, and it worked in earlier versions of PuTTY, you can use this
-option to switch back to doing it the old way.
+To fully revert to the previous behaviour, you'd also need to specify
+\c{-legacy-charset-handling} (see the next section). (Even without
+that option, prompt handling with \c{-legacy-stdio-prompts} may not be
+fully Unicode-clean.)
 
-\c{-legacy-stdio-prompts} makes the tools use the redirectable I/O
-channels for prompts, instead of talking directly to the console. So
-if you were relying on being able to redirect prompt input and output,
-you can use this option.
+\S2{using-cmdline-legacy-charset-handling} \i{\c{-legacy-charset-handling}}:
+handle character set in prompts like older versions of PuTTY
+
+This option applies to PuTTY (on all platforms), and also to all of
+PSCP, PSFTP and Plink on Windows.
+
+In current versions of PuTTY, when you are prompted in the terminal
+window for things like SSH usernames and passwords, the responses you
+type are interpreted as \i{Unicode}, and transmitted to the server as
+such, even if the terminal is otherwise configured to use a different
+character encoding (see \k{config-charset}). Similarly, the same
+prompts from the Windows console tools will unconditionally interpret
+their input as Unicode.
+
+This behaviour is in line with the SSH standards; it allows things
+like usernames to use the full character set of the user's native
+language, and ensures that different keystrokes you type for your
+password are actually treated distinctly.
+
+However, if you are used to the behaviour of the PuTTY tools up to
+version 0.81, this could cause a previously working username and/or
+password not to work as you expected. For instance, if you had set a
+password including some \i{accented characters}, this change in
+behaviour could cause the same keystrokes you've always entered to
+start sending a different sequence of bytes to the server, denying you
+access (and you wouldn't even be able to see the difference, since the
+password is not shown when you type it).
+
+\c{-legacy-charset-handling} reverts the PuTTY tools' behaviour to how
+it was previously: what you type at these prompts will be interpreted
+according to the \q{Remote character set} (for PuTTY) or Windows'
+default character set (for the Windows console tools).
+
+(For example, this could allow you to log in to change your password
+to make using this option unnecessary in future. But if you're doing
+that, make sure the terminal is configured as UTF-8!)