diff --git a/lib/spack/spack/database.py b/lib/spack/spack/database.py
index 428e1cf62ef..a2b91b23661 100644
--- a/lib/spack/spack/database.py
+++ b/lib/spack/spack/database.py
@@ -79,7 +79,7 @@
 #: DB version.  This is stuck in the DB file to track changes in format.
 #: Increment by one when the database format changes.
 #: Versions before 5 were not integers.
-_DB_VERSION = vn.Version("7")
+_DB_VERSION = vn.Version("8")
 
 #: For any version combinations here, skip reindex when upgrading.
 #: Reindexing can take considerable time and is not always necessary.
@@ -92,6 +92,8 @@
     (vn.Version("0.9.3"), vn.Version("5")),
     (vn.Version("5"), vn.Version("6")),
     (vn.Version("6"), vn.Version("7")),
+    (vn.Version("6"), vn.Version("8")),
+    (vn.Version("7"), vn.Version("8")),
 ]
 
 #: Default timeout for spack database locks in seconds or None (no timeout).
@@ -140,6 +142,7 @@ def reader(version: vn.StandardVersion) -> Type["spack.spec.SpecfileReaderBase"]
         vn.Version("5"): spack.spec.SpecfileV1,
         vn.Version("6"): spack.spec.SpecfileV3,
         vn.Version("7"): spack.spec.SpecfileV4,
+        vn.Version("8"): spack.spec.SpecfileV5,
     }
     return reader_cls[version]
 
diff --git a/lib/spack/spack/spec.py b/lib/spack/spack/spec.py
index cde38efce79..c29c8180274 100644
--- a/lib/spack/spack/spec.py
+++ b/lib/spack/spack/spec.py
@@ -198,7 +198,7 @@
 )
 
 #: specfile format version. Must increase monotonically
-SPECFILE_FORMAT_VERSION = 4
+SPECFILE_FORMAT_VERSION = 5
 
 
 class InstallStatus(enum.Enum):
@@ -620,42 +620,11 @@ def complete_with_defaults(self) -> None:
             self.target = default_architecture.target
 
 
+# FIXME (compiler as nodes): remove this class
 class CompilerSpec:
-    """The CompilerSpec field represents the compiler or range of compiler
-    versions that a package should be built with.  CompilerSpecs have a
-    name and a version list."""
-
-    __slots__ = "name", "versions"
-
     def __init__(self, *args):
         raise SystemExit("CompilerSpec is being removed")
 
-    @staticmethod
-    def from_dict(d):
-        d = d["compiler"]
-        return Spec(
-            f"{d['name']}@{vn.VersionList.from_dict(d)}", external_path="/dev-null/", concrete=True
-        )
-
-    @property
-    def display_str(self):
-        """Equivalent to {compiler.name}{@compiler.version} for Specs, without extra
-        @= for readability."""
-        if self.concrete:
-            return f"{self.name}@{self.version}"
-        elif self.versions != vn.any_version:
-            return f"{self.name}@{self.versions}"
-        return self.name
-
-    def __str__(self):
-        out = self.name
-        if self.versions and self.versions != vn.any_version:
-            out += f"@{self.versions}"
-        return out
-
-    def __repr__(self):
-        return str(self)
-
 
 @lang.lazy_lexicographic_ordering
 class DependencySpec:
@@ -2625,8 +2594,10 @@ def from_dict(data):
             spec = SpecfileV2.load(data)
         elif int(data["spec"]["_meta"]["version"]) == 3:
             spec = SpecfileV3.load(data)
-        else:
+        elif int(data["spec"]["_meta"]["version"]) == 4:
             spec = SpecfileV4.load(data)
+        else:
+            spec = SpecfileV5.load(data)
 
         # Any git version should
         for s in spec.traverse():
@@ -4825,7 +4796,7 @@ def from_node_dict(cls, node):
 
         if "compiler" in node:
             # Annotate the compiler spec, might be used later
-            spec.compiler_annotation = CompilerSpec.from_dict(node)
+            spec.compiler_annotation = cls.legacy_compiler(node)
 
         propagated_names = node.get("propagate", [])
         for name, values in node.get("parameters", {}).items():
@@ -4873,6 +4844,13 @@ def from_node_dict(cls, node):
 
         return spec
 
+    @classmethod
+    def legacy_compiler(cls, node):
+        d = node["compiler"]
+        return Spec(
+            f"{d['name']}@{vn.VersionList.from_dict(d)}", external_path="/dev-null/", concrete=True
+        )
+
     @classmethod
     def _load(cls, data):
         """Construct a spec from JSON/YAML using the format version 2.
@@ -5079,6 +5057,12 @@ def load(cls, data):
         return cls._load(data)
 
 
+class SpecfileV5(SpecfileV4):
+    @classmethod
+    def legacy_compiler(cls, node):
+        raise RuntimeError("The 'compiler' option is unexpected in specfiles at v5 or greater")
+
+
 class LazySpecCache(collections.defaultdict):
     """Cache for Specs that uses a spec_like as key, and computes lazily
     the corresponding value ``Spec(spec_like``.